It seems logical. The way to kick-start your journey to a fitter, healthier and – let’s face it – more toned version of your post-holiday self is to work out until you are dripping in sweat. Finishing a workout drenched certainly feels like you’ve achieved something. And some people are even cashing in on this idea with gym kit that makes you sweat more during your workout and, supposedly, lose more weight too.
No sweat: The smart guide to exercise
Forget the latest fad – here’s our evidence-based guide to workout success, and the truth about the advice you can ignore
But feelings can be deceptive. “Sweat is not a guide that can signal benefit as a result of exercise,” says at McMaster University in Ontario, Canada. “It’s an indication of your physiological need to dissipate heat load. When you sit in a sauna you sweat, but do people think that has the same benefit as exercising?”
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Regardless of temperature, some of us are simply prone to sweating more, says of Imperial College London, whose work has shown how exercise benefits your heart. Genetics plays a part, as does how fit you are to begin with. Perhaps surprisingly, research shows that people perspire because their body adapts to dealing with the effort, and sweating more helps them keep cool. And men when they exercise.
When it comes to getting fit, moderate exercise that gets you moving but not necessarily sweating can do the job, says at the University of Oslo in Norway (see “No sweat: When, how and how much should I exercise?”). “You need to get your pulse up, but that would be sufficient,” he says.
You can also forget the idea that sweating more leads to weight loss – you may be a bit lighter, but it’s just the water you have lost. That sweat-inducing gym gear is no better than turning up the thermostat. So if the person next to you is sweating buckets, don’t assume they are working harder. Sweating your butt off is irrelevant to health, says O’Regan. “Sweating is a poor indicator of energy use, with much variation between individuals, and it certainly isn’t a measure of the benefit of exercise,” he says.
Does slow exercise burn more fat?
It is the perfect carrot to dangle if you are more likely to be sliding off the couch than running out of the door: exercising at lower intensities can burn more fat than a strenuous workout. This idea of the “fat-burning zone” starts with the fact that the body can quickly turn carbohydrates into fuel, so they are called upon in an intense workout – whereas fat is burned more slowly, making it an ideal fuel for a slower pace.
Unfortunately, that is a bit of a confusing message, says sports scientist Chris Easton at the University of the West of Scotland, UK. At very low intensities we burn proportionally more fat than carbohydrate – but the amount of both burned will be much higher at higher intensities, says Easton. So unless you are prepared to keep going for a very long time, you are better off getting your skates on.
Should I exercise on an empty stomach?
Carbohydrates are a more readily available source of fuel than fat, so by exercising on an empty stomach with less circulating carbohydrate – for instance first thing in the morning – your body will be forced to use fat instead. Right?
To put this folk wisdom to the test, and colleagues at the University of Bath, UK, asked obese men to walk for an hour on a treadmill either on an empty stomach or after a carb-heavy breakfast. Sure enough, samples taken from their fat tissue afterwards showed that in those who had fasted, but not in those who had eaten.
Not so fast, says sports scientist Chris Easton at the University of the West of Scotland, UK: with more intense exercise, this approach probably won’t work. “The counterargument is that if you are trying to do high-intensity exercise without the carbohydrates, you’ll actually suppress the intensity of the exercise,” he says, limiting your body’s ability to adapt to the work you are doing. So while it’s a fine approach for a leisurely jaunt, if you’re trying to improve your personal best, it’s probably a fat lot of good.
This article appeared in print under the headline “Does a good workout mean sweat?”
