Science of Running

Alex Hutchinson rounds up the latest research in endurance sports

Alcohol and running

Although many runners like to finish their day with a few drinks, research suggests the two habits are linked, since the same reward pathways light up in your brain after running and drinking. So it was bad news when researchers at New Zealand’s Massey University published a study last year showing that “moderate” alcohol consumption immediately after a workout delayed recovery from muscle soreness in the following days. The catch: the “moderate” dose of one gram of ethanol per kilogram of bodyweight corresponded to about 6.5 bottles of 5 per cent-alcohol beer for the rugged Kiwi test subjects, who weighed an average of 88 kg.

The same researchers have now followed up with another study, published in the European Journal of Applied Physiology, using half the amount of alcohol – and the news is good. Muscle recovery following a challenging lower-body workout was identical between the alcohol and control groups. “The lower dose is certainly a safe option,” says Matthew Barnes, the lead researcher. For a 70-kilogram adult, that dose corresponds to about 2.6 standard beers or three 125-ml glasses of wine.

Sitting kills

One of the nice things about running for an hour or two is that you don’t feel guilty about sitting at a desk or lying on the couch for the rest of the day. At least, that used to be the case. But recent research suggests that sitting or lying motionless for more than a few hours at a time leads to changes within your muscles that have serious health implications. Last year, a study of 123,000 men and women (ages 50 to 74) found that those who sat more than six hours per day were 18 per cent (for men) or 37 per cent (for women) more likely to die during the 13-year study period than those who sat less than three hours per day. Crucially, that relationship held true no matter how much the subjects exercised.

A new study in the European Heart Journal now offers some practical advice for those whose jobs require prolonged sitting. Australian researchers used accelerometers to measure minute-by-minute activity levels in 4,757 people. Once again, greater amounts of sedentary time were associated with elevated risk of conditions like heart disease. But the accelerometers were also able to record breaks as short as a minute that interrupted sedentary time. The number of breaks taken by the subjects throughout the week ranged from 99 to 1,258, and the researchers found that those who took the most breaks were significantly healthier (for example, their waistlines were 4.1 cm smaller) than those who took the fewest breaks – independent of the total amount of sedentary time they accumulated.

Thermostats and weight

Canadians may be squandering their best advantage in the battle against obesity, according to researchers at University College London in Britain. In a recent review they point out that typical indoor air temperatures during the winter have jumped by several degrees over the last few decades in the northern hemisphere. That means we don’t have to burn as many calories keeping our bodies warm, and it also means that we’re less likely to have helpful “brown fat” that produces heat and burns more calories. The difference could add up to as much as eight kg over a decade, they calculate – though it’s not clear whether increased hunger would eliminate these gains.

“Increased time spent indoors, widespread access to central heating and air conditioning, and increased expectations of thermal comfort all contribute to restricting the range of temperatures we experience in daily life and reduce the time our bodies spend under mild thermal stress – meaning we’re burning less energy,” says lead researcher Fiona Johnson. “This could have an impact on energy balance and ultimately have an impact on body weight and obesity.”

Antioxidants and endurance

Evidence continues to mount that antioxidant supplements like vitamins C and E may interfere with the benefits of exercise and training. The latest study comes from researchers at the University of Queensland in Australia, who administered vitamin E and another antioxidant called alpha-lipoic acid to rats who trained four times a week for 14 weeks. Compared to a control group, the antioxidants suppressed the growth of mitochondria (the “power plants” of your cells), which is one of the primary adaptations to endurance training. The results will appear in the journal Medicine & Science in Sports & Exercise.

Previous studies in humans have found that antioxidants block the improvements in insulin sensitivity that usually accompany exercise, and may also delay muscle recovery after training. The usual argument in favour of antioxidants is that they neutralize damaging “free radicals” associated with aging and disease. But exercise itself is an antioxidant, teaching the body to produce more and more of its own antioxidants. Researchers now believe that taking too many supplements means the body never learns to adapt on its own.

Bogus bracelets

If you’re not sure how a rubber bracelet with a hologram is supposed to “optimize the body’s natural energy flow” and improve strength, endurance and flexibility, you’re not alone. Still, enough people bought into the claims made by Power Balance that they sold a reported $35 million worth of bracelets in 2010, and attracted endorsements from sports superstars like Shaquille O’Neal. But consumer protection officials in Australia have struck a blow for science. When Power Balance couldn’t back up its claims, it was forced to issue a statement acknowledging “there is no credible scientific evidence that supports our claims and therefore we engaged in misleading conduct.” The company offered refunds to customers in Australia.

The hologram bracelets join a long list of patently ridiculous performance-enhancing charms that have become popular with athletes, like the titanium necklaces worn by marathon record-holder Paula Radcliffe. A recent Harvard Medical School study offers one possible explanation: they found that 59 per cent of patients with irritable bowel syndrome reported significant improvements in their symptoms when they were given a placebo – even though they were told the pills contained nothing but sugar, and the bottle was labelled “placebo.” Apparently some things work even when we know perfectly well that they shouldn’t.