The Fitness Wars Are Futile
I’ve put up a permanent page called Fitness Wars because I thought it should be a little “sticky.” It discusses the very strange culture of strength trainers who seem to react to cardio and aerobics with a crucifix held at arms length.
It’s a very odd response to a very important component of health and fitness conditioning and wellbeing programming.
Anyway, I’ve explored some of the origins of this antagonism and I take a look at aerobic conditioning in this context.
Burn That Belly Fat With High-Intensity Training?
Photo: Soldiersmediacenter. Jarad Bargas
A recent study by researchers at the University of Virginia found that high-intensity exercise training disposed of more belly fat in obese middle-aged women than lower-intensity training of the same energy expenditure.
The idea that doing high-intensity interval training burns off stubborn fat and visceral belly fat has been around for quite a few years. The premise has always lacked strong evidence in my opinion — or at least reasonable qualification. Any number of internet training and fat-loss gurus are promoting this idea.
What is High-Intensity Training?
First up, we need to get the concept straight. What exactly is the ’interval training’ or ‘high-intensity training’ or ’high-intensity interval training (HIIT)’ that we hear so much about?
Interval training is intermittent training, often near your maximum, in which you do a lap of an oval, or a spin on a bike, or 60 seconds on a treadmill very fast, then you recover, and do it again several times. That’s simple enough.
For example, I’m a masters sprinter and in training I might do 10 x 100 metres at 95% capacity, or 10 x 40 metres at 100% capacity. This is high-intensity interval training in real life. But I’ve been a marathoner and triathlete as well (don’t ask), and high-intensity training for those disciplines is mostly entirely different; say, 2km fast, 2km slow, 2km fast; or 6 x 400 metres at 90% capacity, or even, I might add, 5km at race pace, which is still high-intensity training, even if not interval training. And further, I know that if you run 40 to 60 miles a week in marathon or triathlon training you’ll burn fat . . . lots of it. So what’s this HIT stuff all about?
Early Investigations Were Not Adequate
One problem with some of the earlier studies was that they did not set a rule for what constitutes ‘high intensity’. The study I quoted above used lactate threshold to determine this, an excellent idea. And few earlier studies actually compared the different intensities for the same energy expenditure, which is what needs to be done to get a reasonable comparison.
You can’t just do 6 spins on a stationary bike for 30 seconds flat out and expect to burn the same amount of calories and fat as someone who does 30 minutes on the treadmill at 85% capacity, or even a 90-minute run at slow pace for that matter. Energy expenditure, which just about always includes some fat and glucose burning, is going to be a product of intensity X time for any physical activity.
In that event, the best approach for fat loss and fitness goals is likely to be a combination of interval training, weight training and cardio at different intensities. Big surprise eh? No, that’s right, it’s not. It almost reflects the recent exercise guidelines issued by the US government for general health and fitness.
Persistent Abdominal Fat and How to Shed It
What the study above suggests is that high-intensity training just might be superior to to lower-intensity training, for equal energy expended, in removing belly fat, especially the visceral fat wrapped around the internal organs that has been shown to increase your risk of heart disease and type 2 diabetes. Naturally, you have to include a nutrition program with some calorie restriction as well.
Even though the study involved a small number of women, 27, it seemed to be well designed. And yet men might respond differently, as might the young or post-menopausal women. It’s an idea that has promise for designing exercise programs for the overweight and people with metabolic syndrome and diabetes and is well worth watching in the future. The main problem is one that is not going to be easily solved: that unfit, obese people are unlikely to take on high-intensity training by themselves and stick to it, despite what you see on The Biggest Loser.
Having said that, there is plenty of evidence that aerobic, cardio type programs help people lose fat in general — even some visceral fat — and aerobic exercise has additional benefits for cardiovascular protection. A combination of weights, cardio and HIT is likely to be the superior program if it can be tolerated.
The Best Type of High-Intensity Training for Obesity?
Heavy people exert quite a shock to the knees when they run long or hard. It’s a real injury concern. Running is often out of the question for obese people, let alone high-intensity running. For this reason, I favour cycle spin classes on a stationary bike. Doing this exercise in a group has advantages. The instructor will encourage hard work, but it’s possible to set your own pace by adjusting resistance and peddle cadence if you get overwhelmed. You’ll get some high-intensity work threaded with lower-intensity cardio — an excellent workout combo. A medical checkup is highly recommended for anyone moving from a sedentary lifestyle to high-intensity training.
Does Stretching Work for Injury Prevention or Performance?
If you’ve been involved in any sort of physical activity for fitness or sports, you probably know that ’stretching’ is highly recommended for the following reasons:
- Increase or maintain flexibility to prevent injury and increase mobility for day-to-day living
- Prevent injury during sports and exercise activity
- Increase performance in sport
- Offset muscle soreness after exercise
It seems to make sense doesn’t it? You feel that muscle let go and you think to yourself: “if only that muscle was a little more flexible, that would not have happened.”
The trouble is, much of the value of stretching got taken for granted over many decades and few scientific studies were undertaken to confirm what everyone assumed was correct: you must stretch.
Now, some of that scientific work on stretching has been done and it’s not quite as simple as logic would have us believe.
Maintain flexibility
To cut to the chase, stretching on a regular basis, perhaps daily, seems to be a good idea for everyone. Regular stretching probably has benefits for increased mobility, balance and injury prevention, especially as we age.
Prevent injury during exercise and sports
While regular stretching of various types may help athletes overall, stretching before or after an event or workout has mixed support for injury prevention, which I’m sure comes as a surprise to many. We all do it in some form because it makes us feel ready to compete. Benefits may be more psychological than physical. However, some recent review studies have been more positive, especially in relation to muscle-tendon injuries. Inadequate study design and confusion of the terms ’stretching’ and ‘warmup’ seems to have confounded much of the early science.
Enhance performance
Static stretching, it seems, may even impair performance in power sports like sprinting and jumping by interfering with optimum stretch-shortening cycle. It’s best not to confuse static stretching with warmups, in which dynamic stretching probably has a place.
On the other hand, some sports like gymnastics and dance require extreme flexibility and the same rules may not apply.
Overall, static, passive of PNF (proprioceptive neuromuscular facilitation ) stretching close to your sport or activity — before or after — seems to have little going for it in relation to performance benefit.
Prevent muscle soreness
Soreness after an exercise session is called ‘delayed-onset muscle soreness’ or DOMS. Stretching before or after exercise has long been recommended as a way to reduce or prevent soreness. However, a review of studies in this area did not find any benefit from stretching for the prevention of muscle soreness. Warming up is something different and has more calculable benefits.
Summary of stretching
In summary, the best advice seems to be that we maintain a regular stretching program from day to day, warm up sufficiently before exercise and sport, including some dynamic stretches — leg swings, arm swings are a good example — then warm down with some further stretches, but don’t expect that either performance or muscle soreness will benefit from static stretching at exercise time.
I’m certain this will be debated for many years to come.
- Small K, Mc Naughton L, Matthews M. A systematic review into the efficacy of static stretching as part of a warm-up for the prevention of exercise-related injury. Res Sports Med. 2008 Jul-Sep;16(3):213-31.
- Hart L. Effect of stretching on sport injury risk: a review. Clin J Sport Med. 2005 Mar;15(2):113.
- Herbert RD, de Noronha M. Stretching to prevent or reduce muscle soreness after exercise. Cochrane Database Syst Rev. 2007 Oct 17;(4):CD004577. Review.
How to Boost Immunity With Diet and Exercise
Photo by ktylerconk
How many times have you seen an ad for some wonder ‘erb or other that’s supposed to boost the immune system. It’s echinacea today and some Chinese herb the next, as well as a vast array of products that the supplement industry claim “support the immune system” — whatever that means.
Diet and Immunity
I’m not suggesting that diet and nutrition don’t have an important role to play in maintaining a healthy immune system. Meeting the recommended intake of macronutrients, vitamins and minerals and fats, and consuming copious quantities of antioxidant nutrients as part of healthy eating is bound to promote good immune system function — as far as it goes. However, the evidence for consuming individual dietary components or special foods or supplements beyond the RDI (recommended dietary intake) is mostly speculative or at least inconclusive.
Exercise and Immunity
If you follow a healthy lifestyle approach with healthy eating and a program of physical activity, here are a few things to note about how the immune system responds to exercise:
- A regular, low to moderate intensity exercise habit is associated with a reduced incidence of infection compared with those who do very little exercise or physical activity.
- Heavy, and or prolonged exercise training can impair the immune system, possibly leading to susceptibility to infection, particularly in a period of up to 24 hours after a heavy training session or event.
- Exercising at high intensity for prolonged periods without food — 90 minutes and beyond for example — may make you especially vulnerable to infection as a result of immune system depression.
- Consuming carbohydrate at the rate of 30-60 grams an hour during intense and prolonged exercise can help to maintain immune system function. That’s 1-2 sports drinks and hour or equivalent. (One drink is probably adequate for most situations except for extreme conditions and intensity.)
- Meeting your daily requirements for micronutrients like zinc, iron, and B and C vitamins is essential. Although a multivitamin supplement may help, consuming mega quantities of vitamins and minerals may be counterproductive. See article on Vitamin C and training adaptation.
- A recent review confirmed the value of carbohydrate supplementation and a possible role for vitamin C (note caution above), but no other supplement showed up as useful for heavy exercisers.
It’s worth noting the value of carbohydrate to immunity in a balanced diet and exercise program. Low-carbohydrate intake with low blood glucose, plus the stresses of exercise, increases cortisol production to the point where the immune system is compromised. Low-carb, high-fat diets, especially saturated fat, are not appropriate if you have a robust exercise program. In addition, saturated fat has been shown to impair immune response. Low-carb is not where you want to be if you exercise a lot.
J Sports Sci. 2004 Jan;22(1):115-25. Exercise, nutrition and immune function. Gleeson M, Nieman DC, Pedersen BK.
JEur J Clin Nutr. 2007 Apr;61(4):443-60. Nutritional modulation of exercise-induced immunodepression in athletes: a systematic review and meta-analysis. Moreira A, Kekkonen RA, Delgado L, Fonseca J, Korpela R, Haahtela T.
Scand J Immunol. 2008 Jul;68(1):30 42. Differential effects of a saturated and a monounsaturated fatty acid on MHC class I antigen presentation. Shaikh SR, Mitchell D, Carroll E, Li M, Schneck J, Edidin M.
Food and Fitness Science Roundup
For this regular roundup, I try to find work that tells us something significant or new in the context of the field of study.
New Recommendations for Vitamin D Intake for Children from the American Academy of Pediatrics
A recommendation for a doubling of recommended dietary intake of an essential nutrient for any population sector is substantial news in nutrition science. The AAP list the reasons and the strategy here.
http://www.aap.org/pressroom/nce/nce08vitamind.htm
Coffee Drinking Does not Raise Mortality
Up to 6 cups a day and risks were still normal and even slightly lower than the consumers of much more moderate quantities. Adjustment of cardiovascular risk seems to be the difference — perhaps by lowering the risk of type 2 diabetes?
Ann Intern Med. 2008 Jun 17;148(12):904-14. The relationship of coffee consumption with mortality. Lopez-Garcia E, van Dam RM, Li TY, Rodriguez-Artalejo F, Hu FB.
Also see: Does Coffee Kill or Cure?
Red Wine Seems to Cut Risk of Lung Cancer
What? Not another reason to drink red wine! The authors do counsel against excessive consumption.
Cancer Epidemiol Biomarkers Prev. 2008 Oct;17(10):2692-9. Alcoholic Beverage Intake and Risk of Lung Cancer: The California Men’s Health Study. Chao C, Slezak JM, Caan BJ, Quinn VP.
Vitamin C Interferes with Training Adaptation and Performance
I noticed the possibility of this a few years ago while researching the utility of antioxidants like vitamin C to benefit athletic performance. Vitamin C seemed to inhibit phosphofructokinase, which is an important enzyme in glycolysis (breakdown and use of glucose for energy). Considering that many athletes and fitness buffs seem to take vitamin C supplements, it may be worth noting. Moderate dietary intake is likely not a problem. We need more information on this one before the panic sets in.
Am J Clin Nutr. 2008 Jan;87(1):142-9. Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance. Gomez-Cabrera MC, Domenech E, Romagnoli M, Arduini A, Borras C, Pallardo FV, Sastre J, Viña J.
Caffeine Plus Carbohydrate Increases Glycogen Storage
As far as I am aware, this is the first time this has been shown. About 500 mg caffeine is a lot of coffee though.
J Appl Physiol. 2008 Jul;105(1):7-13. High rates of muscle glycogen resynthesis after exhaustive exercise when carbohydrate is coingested with caffeine. Pedersen DJ, Lessard SJ, Coffey VG, Churchley EG, Wootton AM, Ng T, Watt MJ, Hawley JA.
New Glycemic Index and Load Tables
If you’re into the GI, you’ll need this. More on the GI in another article. I’m not a big fan.
Click through to here from the abstract and you can download the free tables.
Diabetes Care. 2008 Oct 3. International tables of glycemic index and glycemic load values: 2008. Atkinson FS, Foster-Powell K, Brand-Miller JC.
Check out the Food for Life, Fit for Life Training Program. Free download available.
New Exercise Guidelines Released in the US
Pic by Abraaj
New physical activity guidelines have just been released by the US Department of Health and Human Services. As they report 25.6% of adults in the US are medically obese — that’s a body mass index (BMI) of over 30 — there is an air of slight panic about this latest announcement. Here are the new adult guidelines, which include a few changes from previous guidelines.
- Adults should do 2 hours and 30 minutes a week of moderate-intensity, or 1 hour and 15 minutes (75 minutes) a week of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity aerobic physical activity. Aerobic activity should be performed in episodes of at least 10 minutes, preferably spread throughout the week.
- Additional health benefits are provided by increasing to 5 hours (300 minutes) a week of moderate-intensity aerobic physical activity, or 2 hours and 30 minutes a week of vigorous-intensity physical activity, or an equivalent combination of both.
- Adults should also do muscle-strengthening activities that involve all major muscle groups performed on 2 or more days per week.
For more information, the physical activity guidelines site has much more information, including useful suggestions for people not used to exercise, and background information for professionals in the fitness sciences.
Physical activity is not all about losing weight — health advantages can accrue in the absence of weight loss – yet unless obese people can be trained or persuaded to cut calorie intake, getting the fat off will continue to be a struggle.
Low-Carb Diets Make You Dumber and Slower
Photo courtesy Anosmia
Low-carb diets have had their share of weight loss success; and most of it can be attributed to dietary restriction of food choice. That’s how most restrictive diets work, from low-fat to low-carb and vegan: tell people they can’t eat something that’s clearly identifiable, and they will lose weight because choice is curtailed and they find it easier to eat fewer calories.
The trouble starts when they find they can’t maintain such a restrictive regimen — and then they get discouraged, guilty, and the relapse occurs.
But what if low-carb dieting helped you lose weight for the time being, but actually inhibited your personal performance in day-to-day living? Would you continue with it as a lifestyle choice?
What I’m about to discuss does not necessarily apply to moderately low-carb diets, but mostly to ketogenic diets, in which carbohydrate intake is usually less than 20 percent. Even so, there is a possibility that the effects apply across a continuum of low-carb eating from very low to low.
And those adverse effects? Low-carb makes you think slower and move slower.
Low Carb Makes You Dumber
In a study in 2007 in the American Journal of Clinical Nutrition, researchers compared the cognitive abilities of dieters on a low-carb, high-fat (LCHF) diet with another group of dieters on a high-carb, low-fat diet (HCLF) . Here is what they found:
However, the IT test score (a measure of the speed of visual information processing) was affected by diet composition. The results showed that participants consuming the LCHF had significantly less improvement in the minimum stimulus time required to make a correct response than did those consuming the HCLF diet . . . Our findings are consistent with those of an earlier study in obese women showing that performance of a complex, cognitively demanding task assessing mental flexibility was significantly worse after the consumption of a very-low-energy, low-carbohydrate, ketogenic diet than after the consumption of an isocaloric, nonketogenic diet with higher carbohydrate and lower fat content. Similarly, the treatment of young rats with a ketogenic LCHF diet for 1 month resulted in severe cognitive impairment, and a series of rat studies showed that the chronic ingestion of a high-fat diet, in particular a high-saturated-fat diet, can adversely affect cognitive performance.
Low Carb Makes You Slower
In a study in the Journal of the American Dietetic Association in 2007, a team of investigators measured the fatigue and perceived effort of one group of dieters on a ketogenic low-carb diet and another group on a diet with much higher quantities of carbohydrate. Here’s what they concluded:
These pilot data indicate that ketogenic, low-carbohydrate diets enhance fatigability and can reduce the desire to exercise in free-living individuals.
This is not surprising because athletes know that glucose (and phosphocreatine) supply energy at a rate that supports fast, high-powered activities, whereas fat and ketones can only supply energy at a rate biochemically rapid enough for mostly slower activities.
Evidence from the Paleolithic
Now, you might think that would be a good place to leave this discussion — the evidence is reasonably clear — but just for speculative fun, let’s take a look at our evolutionary pre-history and the diets of emerging Homo sapiens — modern humans — in the Paleolithic period of evolution.
About 800,000 years ago, primates moved out of Africa to the north and into Europe to colder climates. This early pre-human form was called Homo erectus, and this species probably evolved into Homo neanderthalis, the Neanderthals, while erectus lived on as a parallel species.
The curious thing is that a second migration of early humans north from Africa started about 50,000 years ago and spread throughout Europe and beyond. It seems that this smart new species, Homo sapiens or ‘intelligent human’, was much more intelligent than earlier species such as erectus and neanderthalis. As far as evolutionary science can establish, Homo sapiens swept all before it and replaced the Neanderthals and erectus with modern humans throughout the world. The other species were out-competed and did not survive.
Paleo Diets and the Evolution of Power and Intelligence
Enthusiasts of Paleo dieting like to contend that early humans were very healthy on a diet mostly of meat, vegetables and some fruit, but virtually no grains or tubers — that is, a low-carbohydrate diet. However, it’s pretty clear that early humans started to eat grains about 20,000 years ago, perhaps earlier, and, according to Richard Wrangham, Elizabeth Pennisi and others, probably ate tubers well before then. See Did Cooked Tubers Spur the Evolution of Big Brains?
Paleontologists have speculated as to why Homo sapiens so dominated the other species in Europe and beyond as they moved into their territory from 50,000 years ago.
Here’s where I speculate that the burgeoning consumption of carbohydrate foods in the form of tubers and grains in East Africa, the cradle of early humans, fed a growing brain that thrives on glucose. Glucose from carbohydrates supplied abundant energy substrate for the evolving brain to build those complex neural networks that we know provides the complex reasoning capabilities of modern humans.
Carbohydrate foods were abundant in the East African savannah. As Wrangham points out: “Today, there are 40,000 kilograms of tubers per square kilometer in Tanzania’s savanna woodlands.” The book The Lost Crops of Africa, documents the prolific grain resources in this region. It would be unlikely if the evolving Homo sapiens did not take advantage of these abundant food resources at some time.
The Neanderthals, by comparison, most likely had a more limited food supply, relying mostly on meat and some vegetables and fruits in season, and eggs but fewer carbohydrate resources, especially in the cold north.
I think it’s a fair bet that Homo sapiens, as they moved north out of Africa from 50,000 years ago, armed with complex brains fueled by rapidly accessible glucose from carbohydrate food resources, simply out-competed the slower moving and thinking Neanderthals and the remaining Homo erectus. Not only were modern humans smarter, they probably moved faster as well.
The thing is, we can still simulate the best qualities of the diets of our ancestors, which were most likely characterised by being low in saturated fat, high in plant foods and fibre, and with sufficient carbohydrate to keep us out of ketosis and to fuel the powerful movement and activity required for good health and fitness.
High carb. Simply smarter, faster.
American Journal of Clinical Nutrition, Vol. 86, No. 3, 580-587, 2007
J Am Diet Assoc. 2007 Oct;107(10):1792-6.
When Aerobic Fitness is Not Aerobic Conditioning
Photo: Ernst Moeksis
Aerobic fitness is measured by the volume of oxygen you can process in any given time. This is called your VO2 maximum or VO2max. It’s mostly measured in millilitres of oxygen used per kilogram of bodyweight per minute.
An elite marathon runner might have a VO2 of 80 and an obese, sedentary and very unfit person of the same age around 35.
You mainly get very high VO2 by doing aerobic or cardio training for lengthy sessions, usually in one block; say, an hour or running, cycling or similar activity. But . . . you can also get a reasonably high VO2 — but not as high as a marathon runner — by doing higher intensity exercise for less time. This might involve sprints or middle distance intervals at high intensity, or even workouts like this one in the gym without running at all. Training for team sports can provide this sort of aerobic fitness. Typical VO2 in elite athletes in sports like football (soccer) might be around 60 to 65, with some individuals even higher.
Why You Need Cardio for Health
‘Cardio’ like walking or slow jogging on treadmills is often recommended in heart rehabilitation programs or for the very unfit in order to build up heart and lung fitness. This is much less stressful than doing higher intensity intervals for a shorter time. And regular, moderate-intensity, sustained aerobic exercise conditions other aspects of your body other than your ability to to get fitter faster, which is perceived as one benefit of interval training.
Aerobic conditioning of the longer, slower type builds the small blood vessels called ‘capillaries’, in muscles, — the heart is a muscle — and these are encouraged to grow throughout muscle tissue to facilitate oxygen supply at times of high demand. With this sort of conditioning, your heart has extra blood supply and it gets bigger and stronger as well. For example, in one study, two groups were trained, one doing continuous, cardio type exercise, and the other shorter intervals of higher intensity. The longer, slower cardio group added twice as much capillary capacity as the interval trainers.
This might even be important if you were unfortunate enough to suffer a heart attack. The extra blood supply, called ‘collateral supply’ could save your life.
You will get some of this capillary conditioning with interval training, but the big benefits mostly come from regular, sustained aerobic type exercise — jogging, running, cycling swimming for 30 minutes or more at a session. Naturally, the higher-intensity interval type exercise will improve your anaerobic performance if you need this for sports.
If you’re training for health and fitness, don’t put all of your eggs in the weight training and high-intensity interval training baskets. Find time to fit in some good, old-fashioned cardio.
Effect of interval versus continuous training on cardiorespiratory and mitochondrial functions: relationship to aerobic performance improvements in sedentary subjects. Daussin FN, Zoll J, Dufour SP, et al. Am J Physiol Regul Integr Comp Physiol. 2008 Jul;295(1):R264-72. 2008
Walking is NEAT - Walk More - Lose Weight
As reported elsewhere, I just spent 5 days walking on Fraser Island, a World Heritage island just off the coast of south-east Queensland, Australia. It’s an amazing island built entirely of ocean sand deposits, yet it supports large freshwater lakes and huge forest and scrub wilderness — ideal for hiking with backpacks between specially built walkers’ camps courtesy of the National Parks people. And the dingoes add a little spice to the adventure.
NEAT also happens to be a technical term in the metabolism sciences meaning “non-exercise activity thermogenesis”. This is the activity you do when you’re not doing any formal exercise — things like fidgeting, pacing, being on the move all the time at home or at work and so on. Hauling a 20 kilo pack for 15 kms a day hiking is not necessarily ‘non-exercise’ but the point is that in studies of NEAT in various populations, scientists found that the differences in energy use between NEAT maximisers and neat minimisers can be up to 2000 kcalories a day, and even just standing for two hours rather than sitting for two hours can use around 300 kcalories extra a day.
A team at the Mayo Clinic have studied the NEAT thing quite extensively: “Obese individuals appear to exhibit an innate tendency to be seated for 2.5 hours per day more than sedentary lean counterparts.”
Now that’s really useful to know, because for those of us who run training and weight loss programs for the obese and overweight, it becomes obvious that some people are not going to be able to do any formal exercise program for reasons of size or motivation or disability.
The next best thing — or perhaps even the best thing — is to get them to ramp up their NEAT. Three hundred to 500 kcalories a day in NEAT could be all that some of these people need, along with another 500 kcalories in food energy restriction, to start losing the flab.
Convincing people to move more in their daily lives could be the ’sleeper’ factor is arresting the obesity epidemic. Walking is the dominant form of NEAT, even if it’s around the home, but preferably around the block and not to the refrigerator or local fast food outlet.
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