How fast do we become unfit?

by Dan GordonAnd the Anglia Ruskin University And the Justin RobertsAnd the Anglia Ruskin University

Getting in shape is not easy. But after all that hard work, how long will we actually keep it? It turns out that even the great effort we put into training, taking some time off can mean we become “unfit” much faster than it actually took us to get in shape.

To understand how the body becomes “unfit”, we first need to understand how to become fit. The key to becoming more fit – whether it’s improving cardiovascular fitness or muscular strength – is bypassing.Usual pregnancyThis means doing more than the body is used to. The stress this creates on our bodies causes us to adapt and become more tolerant, which leads to higher fitness levels.

The time it takes to get fit depends on a number of factors, including fitness levels, age, hard workouts, and even the environment. But some studies only indicate that Six sessions of interval trainingIt can lead to an increase in the maximum oxygen uptake (V02 max) – a measure of general fitness – and an improvement in how well our bodies can fuel themselves by using the sugar stored in our cells during exercise.

For strength training, some gains in muscle strength can be demonstrated Less than two weeksBut changes in muscle size won’t appear until around 8-12 weeks.

Cardiovascular health

When we stop training, the speed of fitness loss also depends on many factors – including the type of fitness we’re talking about (such as strength or cardiovascular fitness).

For example, let’s look at the Marathon runner, Who is at peak fitness and can run a marathon in 2 hours and 30 minutes This person spends five to six days a week training, and covers a total of 90 km. They have also spent the last 15 years developing this level of fitness.

Now suppose they have stopped training altogether. Since the body no longer suffers from the stress of training that compels it to stay in shape, the runner will begin to lose fitness within a few weeks.

Cardiorespiratory fitness – indicated by V02 max (the amount of oxygen a person can use during exercise) – will decrease approximately 10% in The first four weeks After the person stops training. This rate of decline continues, but at a slower rate over longer periods.

Interestingly, although highly trained athletes (such as a marathon runner) experienced a sharp drop in their V02 max in the first four weeks, this drop eventually fades, and they are in fact maintaining their V02 higher than the average person. But for the average person, the V02 max dips sharply, returning to pre-workout levels, at Less than eight weeks.

A tired woman takes her breath after a run in the park.

The reason for the decrease in V02 max is due to the decrease in blood and plasma volumes – which are reduced by as much 12% in the first four weeks After the person stops training. The plasma and blood volume are decreased due to Lack of stress They are put on our hearts and muscles.

The plasma volume may be decreased by approximately 5% within The first 48 hours From stopping training. The blood and plasma volume-lowering effect reduces blood flow around the body with each heartbeat. But these levels only drop to where we started – which means we won’t get any worse.

Of course, most of us are not marathon runners – but we also are not immune to these influences. Once we stop exercising, the body will begin to lose these key cardiovascular adaptations at a rate very similar to highly trained athletes.

Strength training

When it comes to strength, the evidence shows that in the average person, 12 weeks without training It causes a significant decrease in the amount of weight we can lift. Luckily, Research It shows that you are maintaining some of the strength you gained before you stop training. The interesting thing is that despite the significant decrease in strength, there is only a slight decrease in the size of the muscle fibers.

The reason for our loss of muscle strength is largely due to the fact that we no longer put our muscles under stress. So when we stop working hard in our muscles, the muscles become “lazy,” which results in a decrease in the number of our muscle fibers, and a reduction in the number of muscles that are recruited during activity – making us less able to lift the heavy loads we are used to. .

The number of muscle fibers used during exercise drops by about 13% after just two weeks of not training – although this does not appear to be accompanied by a decrease in muscle strength. This means that the losses observed over longer periods of non-exercise are a combination of both this initial decrease in the number of muscle fibers we use, but also the slowest decrease in muscle mass.

For the average weightlifting gym goer, they will experience a decrease in the size of their muscles – over time they find it difficult to lift heavy loads because they have fewer muscle fibers to recruit.

So, even after all the effort to get back in shape, we start losing our cardiovascular fitness and strength within 48 hours of stopping. But we haven’t felt these effects for at least two to three weeks for cardiovascular fitness and about 6-10 weeks for strength. Rates for “no training” are similar for men and women, and even for older athletes. But the more fit you are, the slower you will lose your gains.

Dan GordonAssociate Professor: Cardiorespiratory Exercise Physiology, Anglia Ruskin University And the Justin RobertsAssociate Professor, Health and Exercise Nutrition, Anglia Ruskin University

This article was republished from Conversation Under a Creative Commons license. Read the The original article.

It happens to become “unfit” much faster than it takes to become “fit.” New Africa / Shutterstock