Whether you’ve been unwell, on holiday, unable to get to the gym due to lockdown restrictions or something else, when you’re a regular gym-goer, the thought of going back, feeling strong again, being surrounded by like-minded people and getting that endorphin rush can be very exciting.
So when it’s time to get back to the gym, we see many people employ a ‘let’s pick up where we left off’ mentality - after all, when you’ve spent months or years training and putting in the hard work, you can just get straight back into it… right?
Not quite. During a break from exercise, you actually lose strength, coordination and flexibility. While that can feel frustrating given the effort, time and dedication it takes to build up your endurance, agility and fitness, it also affects your injury risk if you try to resume your pre-break exercise routine and training schedule. With Hong Kong restrictions easing and gyms reopening, our physiotherapists thought it would be a perfect time to have a look into what happens to your body during a break from regular exercise, why it matters, and what you can do to return to exercise safely.
What Happens To The Body During A Break From Exercise?
While short periods of rest between exercise sessions are vital in helping the body recover, prevent future injury and improve your subsequent performance,(1) the same can’t be said for longer periods of inactivity.
When you have a break from exercise, the first place you’re likely to notice a change is your cardiovascular fitness. Cardiovascular, or aerobic exercise, refers to exercise that is done over a sustained duration, working the heart and lungs. An example is a longer steady jog, as opposed to a short fast sprint. Regular cardiovascular exercise makes the heart and lungs more efficient at moving oxygen and blood around the body, delivering it to the muscles so that they can continue to produce energy.
Your cardiovascular fitness can begin to noticeably decline within just two weeks of inactivity.(2) As a result, you may notice yourself getting more puffed than you’re used to when running up the stairs because your heart has to work harder to get enough blood to your muscles.(3)
The rate of cardiovascular fitness loss can vary depending on many factors such as your age and level of athleticism, meaning the fitter you are, the slower the loss.(4) Endurance athletes have shown a 7% decrease in cardiovascular fitness after 12 days of inactivity, and a 20% decrease after four weeks.(5)
When it comes to muscle strength, a person’s muscle mass decreases when there is no stimulus, causing your muscles to become less efficient and able to exert less power. This is referred to as detraining. This effect can start to be observed within two to three weeks of rest,(6) with one study examining the effects of fourteen days of bed rest on middle-aged adults showing that rapid skeletal muscle loss in the feet and legs was induced.(7)
According to a Head of Athletic Performance Coach, for someone that is athletic, you can expect a decline in speed potential after 2-7 days, in muscular endurance after 10-21 days, in anaerobic endurance after 14-21 days, and in both maximum strength and aerobic endurance after 21-28 days.(8) While this will be faster for the general non-athletic population, it is also influenced by the duration of consistent training, with those that have been regularly training for 12 months, for example, experiencing a lower fitness decay rate when they take time off than those that have recently started their fitness journey. Gender may also play a role, with older women having been shown to lose muscle mass more rapidly than other demographics.(9)
What If Your Fitness Levels Were Very High Before Your Break?
The fitter you are, the faster a decline will occur compared to a less fit counterpart,(10) until you reach a plateau, with fitness loss after this being more gradual.(11) This is because the body is used to regular training at a higher level, making the changes to your fitness more noticeable. Those with a lower fitness baseline are more likely to experience a slow fitness decline in the first few weeks, however, after 4-8 weeks fitness is likely to drop away completely to a minimal level.(12)
This all means that even if you had a high fitness level, our gym closures are likely to still have had a significant impact - and you need to take it slow and return to exercise gradually, which means:
Build Up Slowly
While it is difficult to predict exactly how long it will take you to regain your previous fitness level, it’s likely that it won’t take you as long as it did in the first place, thanks to muscle memory.(13) Your muscles have special cells that ‘remember’ previous movements, allowing you to build lost muscle and cardiovascular fitness faster than you initially may have.
However, it is still important to build up gradually to protect against injury or excessive fatigue. For strength training, a good rule of thumb is to start at a comfortable level (try between 50%-70% of your original weight or intensity levels), and increase this by no more than 10% each week until you reach your goal. This 10% increase can come from different places, such as increasing your lifting weight by 10%, or increasing your repetitions by 10%. Aim to increase only one aspect of your exercise at a time, and to increase the number of repetitions before increasing weight.(14)
This principle can also be applied to cardiovascular fitness. You can increase the distance you travel, your speed, or the level of difficulty, for example by going up hills, or running with light ankle weights.(15) We find increasing the volume before the intensity (speed or difficulty level) safer from an injury standpoint.
Retaining Your Fitness In The Future
If you want to better control fitness loss for periods of holidays or other circumstances in the future, the good news is that maintaining fitness requires significantly less work than building it. A recent study examined adolescent athletes that had been regularly training for over a year, and then as part of the study began performing significantly less exercise - though still performing lighter movement almost daily - as part of a ‘detraining’ protocol for three weeks. Interestingly, their muscle strength and sports performance was not affected.(16)
The general rule for maintenance is 2 strength sessions and 150 minutes plus of moderate physical activity each week.(3) In practical terms: just try to maximise your movement over your days. Say yes to those evening walks, take the stairs, walk to the shops or take the bike, play a social sport - it all counts.
Common Injuries Our Physios See When Returning To The Gym
After some time off, the most common injuries we see are clients either exercising at the same intensity as before their break without accounting for fitness or strength loss, or not allowing adequate rest between sessions.(17) Both result in overtraining and overreaching, both of which can place a demand on the body that can lead to injury, as well as body adaptations that can be detrimental to performance.(18)
Common injuries seen from overtraining are predominantly soft tissue injuries(19) such as ligament strains. We often see these in the back or shoulder from lifting a weight that is too heavy, or performing exercises with improper form. The Achilles and knees are other common areas of injury. Stress fractures also result from going too hard or too fast.(20)
Delayed Onset Muscle Soreness (DOMS)
In the case of DOMS, it is normal to feel muscle soreness after an extended break,(21) with peak soreness occurring at 48-72 hours post-exercise.(22) This is where exercise is proven to be the most effective means of alleviating pain during DOMS,(21) so engaging in active rest days (such as going for a long slow walk or swim) is a good way to help manage DOMS pain.
Returning To The Gym After Time Off: Summarised
- Periods of inactivity cause declines in strength and fitness, which is why ‘picking up where you left off’ at the gym is a gateway to potential injury
- After two weeks of inactivity, you may notice a change in your cardiovascular fitness, such as feeling more puffed. This is because blood and oxygen aren’t being moved around your body as efficiently
- Muscle may also noticeably decline after two weeks, but this may occur more gradually
- The fitter you are, the less the decline may be noticeable initially
- You may rebuild your fitness and strength faster after a break than you did initially
- When returning to the gym, start at 50% to 70% of your original weight or intensity levels
- Increase an aspect of exercise by 10% each week. This may look like the weight or the repetitions for weight, and the distance or speed for aerobic fitness
- For periods of inactivity in the future, 2 strength sessions and 2-3 hours of cardio per week can help you maintain your strength and fitness
- DOMS is normal when returning to exercise after a break
- Soft tissue injuries are commonly observed by physiotherapists when returning to exercise after periods of inactivity