The Science of Running

By Alex Hutchinson Performance in a (Legal) Bottle

There are two main categories of performance aids for running: those that work but are banned, and those that are legal but don’t work. There are, however, a few rare options that sit at the intersection of those two categories, offering a modest and perfectly legitimate boost to your race times.

Caffeine

It ’s the most widely used performance-enhancing substance out there, not just in sport but in life. It works by interfering with the build-up of a brain chemical called adenosine that’s associated with mental fatigue, meaning that it makes holding your race pace feel a little easier. A typical dose is about 3 mg of caffeine per kilogram of bodyweight, taken roughly an hour before race time. You can get that from caffeine pills, or from a cup of coffee, though the exact caffeine content of coffee is harder to determine. You can also get caffeine from gels, and there’s some evidence that taking an extra hit of caffeine late in a long race (like a marathon) might give you a boost.

Beet Juice

Over the past decade, beet juice – and, more recently, concentrated beet shots and even beet bars – have emerged as a widespread endurance booster. The high nitrate levels in beets are converted in your body to nitrite and then to nitric oxide, a powerful molecule that helps regulate blood circulation and, for reasons that still aren’t clear, allows you to run more efficiently, burning less energy to sustain a given pace.

A typical dose would be one 70 ml shot of concentrated beet juice, which is equivalent to about 300 ml of juice, the night before a race, and then another one or two shots about three hours before the race. A company called Beet-It makes sport-specific products with standardized levels of nitrate. One caveat: if you use strong antibacterial mouthwash, you’ll deplete the population of microbes in your mouth that convert nitrate to nitrite, thus weakening the effect. A more serious caution: beet juice can mess with your digestive system, leading to diarrhea. This is something to try in a race only if you’ve trialled it successfully in training several times.

Baking Soda

Like caffeine, this is one you’ve already got in your cupboard. The idea is simple: when you exercise intensely, your blood and muscle cells become progressively more acidic. Baking soda is a base (think back to those baking-soda-and-vinegar volcanoes) that helps counteract this rising acidity, allowing you to keep exercising at a high intensity for longer. A typical dose is 0.3 grams per kilogram of bodyweight – and a side effect that’s not unusual, as with beet juice, is stomach upset.

Another option with the same basic goal ( but less chance of stomach upset) is beta-alanine, an amino acid that counters acidity directly in your muscle cells instead of, like baking soda, in your bloodstream. You take beta-alanine over a longer period of time: for example, 3 to 6 grams daily for four to eight weeks. Both of these buffering options are most relevant for short, intense races lasting between one and 10 minutes, but there’s some evidence that even in longer races they can help improve your finishing sprint .

Sauna

This one isn’t a pill or a powder – it’s a luxuriously relaxing way to decompress after a run, with the added bonus of possibly boosting your performance. Repeated exposure to heat triggers a series of adaptations in your body that help you handle hot weather. This is why heat training is crucial if you’re planning to compete in hot weather, say at the Tokyo Olympics. But some scientists now believe that heat adaptation may also boost your performance even in cool-weather racing. One theory: heat exposure triggers an increase in the volume of blood plasma circulating through your body, which makes it a little easier to ferry oxygen from your lungs to your muscles.

The usual forms of heat training involve f lying to Florida or sweating away on a treadmill in a specially designed heat chamber. But there are some attractive (and practical) alternatives. At the end of a run, when your core temperature is already elevated, hitting a hot tub or sauna to keep your core temperature elevated above 38.5 C for another 20 to 30 minutes may do the trick. One study found that just four post-run sauna sessions at 87 C was enough to elicit a plasma boost.

Putting it all together

Depending on which study you look at, each of these performanceboosters might in theory drop your race times by a per cent or two. That makes it tempting to try all of them at once, in search of a mammoth five-per-cent breakthrough. Unfortunately, when researchers try combining multiple performance aids, the math doesn’t seem to work that way. Instead, the equation seems to be 1 + 1 + 1 = 1. More isn’t necessarily better.

It’s not clear why this is the case, but one theory is that all these seemingly different performance aids are ultimately acting on the same target: your brain’s perception of effort. Whether you alter your perception of effort by swigging coffee or by using baking soda to turn down the volume on your muscles’ distress signals, the net result is the same – and doing both at the same time doesn’t seem to give you any extra benefit.

With that in mind, it’s worth considering one final performancebooster: motivational self-talk. Research from Stephen Cheung at Brock University has shown that positive self-talk (“You can do this! You’ve trained for this!”) actually reduces the perception of effort at a given pace compared to negative self-talk (“This sucks, I can’t maintain this pace.”). It takes time and practice to turn positive talk into an automatic mid-race response, but it’s free, totally legal, and carries no risk of explosive diarrhea.

Alex Hutchinson is a Toronto journalist specializing in the science of running and other endurance sports.