From Cycling Weekly
Detraining: The truth about losing fitness
The fitness mantra, you must ‘use it or lose it!’ might be a bit of a cliché, but it turns out that this saying perfectly sums up one of the key principles of fitness and exercise – reversibility. At a time of year when it’s tempting to leave the bike in the shed, it’s even more important to maintain fitness.
So long as you train, you can maintain and (hopefully) build your fitness levels. However, stop training and your fitness levels will steadily decline.
The obvious question that you might therefore ask is, “How much fitness will I lose if I decide to take a break, or if I’m forced to stop training because of injury or illness? And how rapidly will this fitness loss occur?” To answer this, it’s important to understand that there are several different components of fitness, including muscular strength, muscular endurance and cardiovascular – heart, lung and circulatory – endurance.
Stop training and the performance decline in each of these components will take place at different rates. So let’s take an imaginary well-trained cyclist and observe what happens to their body over a period of six months following the complete cessation of training.
This is your last training day for the next six months. After today’s ride, you store your bike away, hang up your cycling shoes and join the bulk of Britons who do no regular vigorous exercise whatsoever!
After three days of inactivity, you might expect that your fitness has already begun to decline. In reality, however, the losses at this stage are very small. If you had been training hard prior to day 0, after three days of rest, your cycling fitness is now probably enhanced.
That’s because in those three days, your muscles have had time to fully recover; muscle carbohydrate stores (glycogen) have been topped up, muscle fibres damaged during hard training have been fully repaired, and favourable metabolic changes in the muscles have had time to occur.
Indeed, this peak in performance after a few days of rest is exactly the reason why tapering works, and why you shouldn’t train right up to the day of a big event.
Day 7 (Week 1)
After a week’s complete inactivity, changes begin to occur in the body that result in fitness losses. For example, after three days, your blood volume can be reduced by five to 12 per cent. This means a decrease in the amount of blood your heart can pump – both in terms of amount of blood pumped per beat and total blood volume per minute.
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