The Dreaded Detraining: Why You Shouldn’t Fear It

Being forced to take a break from the thing you love is hard. That’s what triathlete Emily discovered during the pandemic. Having competed for years, she was used to balancing her career and personal life with a grueling training schedule. She knew how to push herself, and she knew how to allow herself time to recover, but taking a long break and going through the process of detraining was something that used to fill her with fear.

Then, like everyone, Emily was forced to stop. Suddenly no swim sessions, no bike workouts, nothing. All the physical activity she was used to structuring her life around disappeared. She temporarily thought about investing in a home gym before deciding to focus on doing some maintenance workouts with what she had while she waited to see what competitions would be possible. After all, she didn’t want to risk deconditioning completely by sitting at home for a few months.

Emily discovered during this time that her body responded well to this change. Pulling back on the intensity and trying new things felt great, and she soon felt revitalized rather than frustrated. Plus, she was finally able to focus on understanding and assisting the few niggling ailments and injuries that she’d developed over the years. 

Looking back, Emily credits this period of mindful detraining with giving her the boost she needed for her competitions. She’s since gone on to smash a few PBs and now understands why she needs to provide herself with an ‘off-season’ every once in a while, knowing that it won’t be challenging to return to her training plan when she does. Emily now knows that her training isn’t linear; it isn’t always about growing and improving. Sometimes it’s about resting and nurturing your body too.

Many people think taking time off means losing all your fitness gains, just like Emily did. But detraining is an integral part of the process. It can look like tapering, deload weeks, or an off-season. It can help your body and your mind in some astounding ways. 

In this blog, we’ll look at what detraining is, the timeline for how long it takes to lose your fitness, how to make a partial detrain a part of your training plan, and how to avoid overtraining and plateauing.

What is detraining?

In short, detraining is a partial or complete loss of your fitness gains. What goes up must come down, in a sense, unless, in this case, it’s maintained by a certain level of training. So, it’s the slow process of undoing all the work you’ve put in to build up your 

Reducing the frequency, volume, and/or intensity of your training will slowly impair your performance measures such as strength, power, speed, endurance, and flexibility. However, this doesn’t happen instantly if you don’t train for a few days. Instead, it’s a slow process linked to your overall level of fitness and each particular physical skill.

How long does it take to lose gains?

As mentioned, this doesn’t happen overnight but takes a while, with the timeline dependent on each particular area of your fitness. 

It’s also important to note that if you’re an athlete who has trained for consecutive years, you’re more likely to hold onto your fitness level for longer. Whereas, if you’ve only recently started working out, your new gains will likely diminish faster.

Here’s a timeline for some of the changes that may occur if you completely cease all training:

First few days of detraining

• Little to no change.
• Sprinting ability is the only area that begins to decrease noticeably in the first few days.

Ten days of detraining

• VO2max declines by around 8%, affecting your aerobic capacity.

Three weeks of detraining

• Levels of adrenaline drop, affecting how ready you feel to train.
• Lactate begins to accumulate quicker, making intense training sessions initially more difficult.
• Levels of muscle glycogen also drop, depleting your energy sources.
• Your peripheral cardiovascular systems show signs of change to your power production: your capillary and mitochondrial density drops, as do your levels of oxidative enzymes. 

Four weeks of detraining

• Continued reduction in VO2max, with less oxygen reaching your muscles. Your heart rate increases to compensate for this, which raises your rate of perceived exertion (RPE).
• You may notice that you exhaust more readily than when at peak fitness.
• If you’re a highly trained athlete, then around this time, you may notice a reduction in your power, eccentric force, or isokinetic strength.

Eight weeks of detraining

• Your heart is less muscular, with the muscle walls of the pumping chamber having reduced in thickness by up to 25%. 

12 weeks of detraining

• VO2max declines by around 20%.
• Any improvement in blood pressure from regular exercise is reversed by this time.
• Improvements in ventilation also fall by up to 14%.

Detraining doesn’t equal inactivity

As you can see, if you completely cease all training, your body will eventually return to how it was before you started doing any regular workouts. However, giving your body a break from a particular sport or fitness plan doesn’t mean you must stop working out altogether. In fact, you can be intentional about detraining and making it part of your process. For example, setting aside one week a month to pull back rather than push forward with your workouts and allow your body additional time to recover.

There are many ways to pull back on your training while staying active. You can reduce your intensity and begin to detrain while still doing a manageable amount of exercise.

There are many ways to pull back on your training while staying active. You can reduce your intensity and begin to detrain while still doing a manageable amount of exercise. For example, reducing the mileage on your cycle or runs, so you keep your muscles moving but without pushing yourself or chasing any goals. 

You can also switch to trying a different sport or workout, not to challenge yourself to become an athlete in something new but to find different ways of using your muscles while giving your usual ones a break. For example, switching up your weightlifting with some yoga or light runs. 

Plus, it’s important to remember that it takes less work than you think to maintain your fitness and avoid altogether detraining. With a few simple workouts each week (why not use your Polar FitSpark™ training guide?), you can prevent significant declines and ensure you don’t have to start from scratch when you pick up the pace again.

How is detraining related to overtraining and plateauing?

Overtraining is when you exercise more than your body is capable of recovering from within the usual couple of days’ rest window. It’s when you do too much either in a short period or keep pushing yourself harder and harder without allowing for any rest.

Overtraining and detraining are connected because they’re at either end of the training spectrum. You can see this illustrated on Polar Training Load Pro, where your status will shoot up to the red Overreaching zone if you are overtraining, or drop down to the grey Detraining zone. Your training load is calculated by analyzing both your strain and tolerance, to see how the amount of effort you are putting in today measures up against how much training you have done recently. 

More specifically, your strain is the average of your cardio or acute training load over the past seven days. Your tolerance is the cardio load from the past 28 days of training, sometimes referred to as your chronic load. Think of strain as your recent fatigue and tolerance and your overall fitness, so the measurement is seeing what your capacity is for training now based on how much you’ve been training recently. Do too much when your tolerance is low and you’ll overtrain. Do too little when your tolerance is high and you’ll begin to detrain.

When you overtrain, you’re much more likely to burn out or injure yourself and then partially or completely stop working out, which means you begin to detrain. Then, when you start training again, you may be doing so from a lower level of fitness than before, so if you jump back into intense exercise again, you’re likely to overtrain once more.

Plateauing is another workout stage related to detraining. You plateau when your body gets so accustomed to the demands of your workouts that your progress gradually comes to a halt. It’s when you’re doing all the work, but the results have stagnated, leaving you wondering why you are putting in all the effort.

The key is always to pace yourself, ensuring you make manageable gains suitable for your experience and fitness. Plus, ensuring you achieve adequate rest through quality sleep and leaving enough time between workouts. It also means allowing yourself to be gently active during detraining to maintain a certain fitness level. So, manage to calmly keep some balance in your physical activity rather than chaotically swinging from overtraining to detraining.

Plateauing is another workout stage related to detraining. You plateau when your body gets so accustomed to the demands of your workouts that your progress gradually comes to a halt. It’s when you’re doing all the work, but the results have stagnated, leaving you wondering why you are putting in all the effort.

One of the ways to handle or avoid plateauing is through mindfully detraining. Pulling back on the intensity of your training schedule and allowing your muscles more time to repair or trying a new sport or workout to give them a break may be what your body needs right now. Many trainers and coaches add ‘deload’ weeks to training plans to ensure a regular detraining period to boost recovery. It’s an active rest week, where you pull back on any intensity while focusing on light, maintenance workouts to hold onto your fitness level.

Are there any physical benefits from detraining?

A recent study from the National Taiwan Normal University looked at a group of endurance-trained male athletes aged 19-26 years and how their bodies responded to two weeks of detraining. They found some interesting trends which indicated potential benefits to taking a break from training:

• Muscle endurance was maintained: while muscle strength was decreased, its endurance wasn’t affected. 
• Muscle mass increased: while a more extended break from training will decrease lean muscle mass, this study showed that two weeks didn’t affect it.
• Anabolic hormones were enhanced: growth hormone levels increased, enabling the body to remodel and repair muscle tissue more during the training break.

Remember, rest is part of the process

As we’ve seen, there’s a big gap between detraining to the point you lose any fitness gains and allowing your body to rest and recover sufficiently. It’s ok to take a rest week, have an offseason, or taper for an event. Often, it will be a crucial time for your physical, psychological, and mental regeneration.

Plus, you can gain performance benefits during this time. It’s not all a loss, as your body uses the time to boost your recovery and make essential repairs. So, in the long run (pardon the pun), you’ll be rewarded for making partial detraining a part of your training plan. Like Emily, you can be intentional and let your body have a break; it will thank you later.

Please note that the information provided in the Polar Blog articles cannot replace individual advice from health professionals. Please consult your physician before starting a new fitness program.