Regular, consistent exercise stimulates a series of physiological and anatomical adaptions that, if you’re a competitor, results in stronger and faster performance.
Why is exercise good for your physical and mental health?
That’s great if you happen to possess a trophy cabinet but, more importantly, from a health perspective, the World Health Organisation suggests regular physical activity slashes the risk of any types of cancer by 8-28%; heart disease and stroke by 19%; diabetes by 17%; and c and dementia by 28-32%.
The key to boosting fitness is to exceed your habitual load, which means doing more than your body’s used to. This stress on our bodies forces us to adapt and become more tolerant, leading to improved fitness.
What happens if you stop exercising?
These health gains are maintained or improved via regular exercise, so it stands to reason that if you stop exercising, you’ll begin what’s called “detraining”. In scientific circles, this is defined as “the partial or total loss of training-induced adaptations, consequent to the reduction or complete cessation of activity”. In Everyman circles, how long it takes for your once powerful back to be swamped by fatty deposits!
“Unfortunately, you cannot store fitness so ceasing exercise starts to eat away at your hard-earned benefits, which would include improvements in blood pressure, a healthier blood-fat profile and healthier heart,” says top endurance coach Joe Beer. “Stop exercising affects all those and often results in weight gain and poorer mental well-being.”
How quickly you lose fitness depends on whether you’re talking about cardiovascular fitness, which is improved by hiking and Parkruns, or strength fitness, like you’d forge if you hit the gym.
Your VO2max is widely regarded as the gold standard for measuring cardiorespiratory fitness. That’s because VO2max refers to the maximum amount of oxygen that muscles can take in, absorb and use during exercise within a specific timeframe. It’s also proven to be a predictor of longevity.
Studies show that you can lose 10% of your VO2max in the first four weeks of inactivity, with the decline slowing after this period. Why the drop’s down to myriad factors and includes reductions in mass, size and thickness of the left ventricle of the heart. Your blood volume – the amount of blood you pump out with every heartbeat – drops, too.
How quickly do you lose cardiovascular fitness?
You actually start to lose cardiovascular fitness after only 48 hours of stopping exercise, but don’t begin to feel the effects for a few weeks.
As for strength training, again 48 hours without pushing, pulling or lifting starts to impact gains. But the real drop-off occurs after around six to 10 weeks. During that time, there’s a double muscular whammy. After two weeks of no strength training, the number of muscle fibres you recruit for specific exercises plummets by around 13%, albeit this might not be associated with a drop in muscular force. These muscle fibres also reduce in size, so overallyou have smaller, fewer muscles to generate force.
Throw in metabolic changes that include decreased insulin sensitivity and alterations in fat metabolism, which can lead to weight gain, and it’s not the prettiest picture if you suddenly stop exercising. Of course, how unpretty a physiological picture this becomes depends on the duration of inactivity, but as a broad brush, rates of “de-training” are similar for men and women, and even for older athletes. But the fitter you are, the slower you’ll lose your gains.
“Ultimately, a small amount of enjoyable exercise is better than a rigorous exercise regime that you stop either due to burnout or injury,” says Beer. “Find what’s fun, what fits your life and keep the benefits coming.”