Everyone knows that exercise comes with a plethora of benefits, such as counteracting the harms of a sedentary lifestyle, supporting cardiovascular health, boosting mood, and even anti-aging... the list goes on and on!
Generally, we at K Sauce encourage everyone to seize every opportunity to get moving, whether it's a five-minute wait for the bus or a break during a long workday.
However, there is one situation where we strongly advise against exercising: when you haven't had enough sleep.
Wait, isn't exercise supposed to energize us?
Many people believe that physical activity can strengthen the body and offset the damage caused by pulling all-nighters or working late. But is this really the case?
When sleep is lacking, is exercising a remedy or does it exacerbate the problem?
How can we determine if we've had enough sleep and if our bodies are ready for a workout? Are there any specific metrics we can use?
If the sleep quality is poor, does that mean all exercise is off-limits?
Today, let's delve into the relationship between sleep and fitness.
It is not recommended to work out when you haven't had enough sleep."
If you stayed up late working or struggled with insomnia the night before, it's best to put your fitness plans on hold for the day.
Exercising on insufficient sleep can have far more negative impacts on the body than the positive effects of working out.
On one hand, lack of sleep directly affects athletic performance, making the body feel 'exhausted' more quickly than usual.
For instance, if you find that you can't lift the weights you usually do, or you're out of breath and sweating after just a few minutes of running, this could be related to not getting enough sleep.
If you continue to push through or don't notice these signs, you might experience dizziness, headaches, palpitations during your workout... and in more severe cases, there's even a risk of sudden death!
It's one thing if it happens occasionally, but if you consistently have poor sleep quality and insist on engaging in high-intensity workouts, not only will your fitness progress suffer, but other bodily functions, such as immunity, may also be affected.
We all know that fitness involves continually pushing beyond our comfort zone to achieve breakthroughs in performance.
During this process, the immune system enters a 'window period' that only leads to a true improvement in physical fitness after adequate recovery from exercise. This window period can last anywhere from 3 to 72 hours.
The 'open window theory' suggests that different exercise intensities require varying amounts of rest afterward.
Moderate-intensity exercise causes only minor immune changes.
As exercise intensity increases and the duration extends (beyond 90 minutes), the body's immune function gradually decreases, and the recovery time needed becomes longer.
If you engage in high-intensity exercise again shortly after, the body's immune resistance to risk is reduced, and the risk of various diseases, including upper respiratory infections, significantly increases.
Many people also enjoy late-night workouts at the gym or going for a night run or bike ride when it's quiet outside. Even if the exercise doesn't affect their performance, the stimulating effects of exercise can further delay sleep onset, leading to a vicious cycle of 'the more you exercise, the worse your sleep gets.'
In summary, if you're not well-rested, don't work out! Not only do we not recommend late-night workouts, but we also advise against exercising to the point where it disrupts your sleep. If you prefer evening exercise, it's best to complete your workout two hours before bedtime.
3 Key Dimensions to Help You Determine: Is Today a Good Day for a Workout?
You might be wondering: Sometimes, I'm not sure if I've had enough sleep. How can I tell if my body is ready for a workout?
Don't worry, here are three tips to help you determine if your body is in the right condition for exercise today.
1️⃣ Did you get 7 to 8 hours of sleep last night? Is your sleep pattern consistent?
If the answer is 'no' to either question, then hold off on exercising!
Sleep, as part of the 'golden triangle' of eating, moving, and sleeping, should always come before exercise. Generally, maintaining 7 to 8 hours of sleep per night is sufficient.
Additionally, a stable circadian rhythm, or a consistent sleep-wake schedule, is also a key factor in assessing sleep quality.
If you sometimes go to bed early and wake up early, and at other times go to bed late and wake up late, without a fixed routine, this can also impact your body's metabolism and athletic performance.
2️⃣ Is your resting heart rate the same as usual? Has there been a significant increase (more than 10%)?
Resting heart rate refers to the number of heartbeats per minute in a calm, awake, and inactive state.
You can monitor your 'resting heart rate' using a fitness watch or wristband. If you don't have these devices, you can also measure your pulse for one minute when you're well-rested and in a calm mood to get a reference value for your resting heart rate.
Typically, the resting heart rate for healthy adults ranges from 60 to 100 beats per minute. Insufficient sleep or not having fully recovered from intense exercise the day before can cause a certain increase in resting heart rate.
If your resting heart rate suddenly increases by more than 10%, it indicates that your body still needs rest and relaxation, and it's best to avoid exercise at this time.
3️⃣ Have you recovered sufficiently from your last workout?
If you've just completed a high-intensity workout, such as two hours of strength training, a 10-kilometer run, or a hike lasting over five hours for most people…
Then, pushing yourself to 'persevere' the next day is likely to not only fail to help your body progress but could also have negative effects.
This is because the body can only improve further if it has had enough time to recover.
This concept is known in exercise science as the 'overarching' theory:
Proper rest allows the body to adapt to the next phase of increased training intensity while enhancing the body's tolerance and even surpassing the original physical capabilities.
However, if the rest period is too short or too long, it can lead to a decline in athletic performance or stagnation.
If your fitness level has remained stable for a long time without improvement, this could be the reason!
For most people, there is also an average recovery time standard. Generally speaking [3]:
For those just starting out in fitness training, the body's regeneration phase is 48 to 72 hours;
For intermediate individuals, it's 24 to 48 hours;
And for high-level athletes, it's 12 to 24 hours.
That means, after high-intensity training, we should at least give ourselves one day of rest.
On this day, avoid attempting high-intensity workouts again!
Moreover, individual feelings are also important: if you experience intense 'muscle soreness' after high-intensity exercise, it means you still need some time to rest.
Later, as the muscle soreness gradually decreases, you can gradually resume your exercise schedule!
Giving the body enough rest time is also for better performance in the next workout.
Didn't Sleep Well but Really Want to Exercise? Here's What You Can Do.
You might also be thinking: Hey, but I really want to move a bit, what should I do?
If you absolutely must exercise, consider reducing the intensity of your workout or engaging in some low-impact physical activities during your spare moments.
At this time, you can mainly refer to the 'heart rate' data:
The heart rate for low-intensity exercise is (220 - age) x 50% to 70%.
If you can keep your heart rate within this range, walking, leisurely cycling, yoga, tai chi, or any other exercise you enjoy are all great choices.
Also, remember that not only 'structured exercise' counts as exercise - being more active during spare moments, avoiding prolonged sitting, such as taking the stairs, getting off one stop earlier and walking home, or stretching more when getting water, these small activities in daily life, when accumulated, can also burn as many calories as a 30-minute run.
How to move during spare moments? I has written about this many times before; send NEAT to check it out.
Of course, the most important thing is: don't worry, fitness results won't change due to one or two missed workouts.
Always remember, before you strive to become stronger and better through fitness, make sure to get a good night's sleep first!
