We all know the importance of sleep. A good night’s rest is a chance for your body and brain to ‘reboot.’ Just as you have to reboot your computer to clear out the information clogging up your hard drive, your body needs sleep as a respite and a chance to clean up and repair. For example, research shows that a specialized lymphatic system, called the g-lymphatics, clears out misfolded brain proteins as you sleep at night. That’s important for brain health! If you don’t sleep enough, this process may not be as efficient and, over time, it may negatively impact brain health. In fact, misfolded proteins are linked with brain aging and Alzheimer’s disease. Plus, sleep is important for immune health and weight control, too.
Unfortunately, despite the importance of sleep, many people have trouble falling asleep or maintaining sleep. According to sleepeducation.org, 30 to 35% of adults experience short periods of insomnia, while 15 to 20% have experienced short-term insomnia, lasting less than 3 months. It’s unfortunate that 10% of individuals have chronic problems falling or staying asleep. These people deal with sleep problems 3 or more times per week. In women, sleep problems become more common during and after menopause, and in both genders, insomnia becomes more frequent later in life. Sometimes, even small lifestyle changes can have a positive impact on sleep quality–like exercise.
There’s already evidence that physical activity, particularly in the morning, is linked with better sleep quality, but what about a specific type of workout–strength training? Can lifting weights, using resistance bands or working against your own bodyweight help you sleep more soundly? A study carried out at Appalachian State University suggests that it can.
Strength Training and Insomnia: Can It Help You Sleep?
For the study, 24 healthy college students did total body strength workouts that lasted 30 minutes. They tackled their workouts at three different times of day, 7 a.m., 1 p.m., or 7 p.m. and wore fitness trackers to monitor their sleep patterns. The results? Regardless of when they exercised during the day, the participants slept more soundly at night. However, they experienced the greatest improvement in time to fall asleep when they worked out at 7 a.m. In fact, the subjects drifted off to sleep almost 45 minutes faster when they strength trained in the morning. However, even when they worked out later in the day, they fell asleep at least 10 minutes faster.
Also encouraging is the fact that participants who lifted at 7:00 p.m. slept more soundly and experienced fewer awakening during the night. Although it’s not clear why exercising in the evening leads to fewer nighttime awakenings, the rise in body temperature in response to strength training is likely a factor. Exercise raises core body temperature and the cooldown and a drop in temperature afterward signal the brain that it’s time to relax and unwind. In the study, strength training was beneficial for sleep regardless of the time of day it was carried out. The key is to do it! But if you’re free to choose your time, you may benefit more from working out at 7:00 p.m. if you have frequent problems with nighttime awakening. If falling asleep is a challenge for you, opt for morning strength training.
Pros and Cons of Strength Training at Different Times
Independent of the impact of strength training timing on sleep, there are other advantages and disadvantages of strength training at various times of the day. For example, body temperature is highest at around 7:00 p.m. When your body temperature is at its peak, your muscles are more supple and flexible. In addition, pain tolerance is greatest in the early evening, so you may push yourself a little harder if you lift later in the day. However, at least one 10-week study found no differences in muscle hypertrophy gains when subjects exercised in the morning versus the afternoon. Both the morning and afternoon lifters boosted muscle size, and the gains were not statistically different. At least short term, whether you train in the morning or afternoon seems to have little impact on muscle gains.
One downside to lifting late in the day is the fatigue and motivation factor. After a long day at work, your drive to push yourself may be lower than it would be earlier in the day. Therefore, a workout after work may be less productive and you may find reasons not to do it! Of course, this depends on the hours you work and the type of job you have. If you sit all day and have a stressful job, a weight training workout might be just what you need to perk up and relieve stress. We’re all a little different from that perspective.
The Bottom Line
Is better sleep another benefit of strength training? Based on limited research, it may help! Studies show that aerobic exercise also improves sleep quality and morning workouts seem to have an edge when you’re boosting your heart rate with cardio. If anxiety or mild depression is interfering with your sleep, the changes in brain chemicals that happen after a workout may help you relax.
One caveat is that one study showed that high-intensity aerobic exercise, like HIIT training, did not improve sleep quality. Overdoing HIIT training without giving your body time to recover can have negative repercussions too. In one survey showed people sleep best when they devote no more than 40 minutes per week total to high-intensity training, training where the heart rate is 90 to 100% of maximum. Sleep quality dropped off with greater weekly minutes devoted to HIIT training. However, sleep quality also suffered when participants spent less weekly time devoted to intense training. So, train intensely, but don’t overdo it!
At the very least, the results of these studies should lay to rest the myth that moderate exercise interferes with sleep. There’s more evidence that it helps than hurts.
References:
· Shape.com. “Time Your Strength Training and Cardio for Better Sleep!”
· J Strength Cond Res. 2015 May;29(5):1378-85. doi: 10.1519/JSC.0000000000000750.
· J Strength Cond Res. 2009 Dec;23(9):2451-7. doi: 10.1519/JSC.0b013e3181bb7388.
· SleepEducation.org. “Insomnia Awareness Day facts and stats”
· Sleep Med. 2010;11(9):934-40.
· National Sleep Foundation. “How does exercise help those with chronic insomnia?”
· LesMills.com. “Are Your Workouts Sabotaging Your Sleep?”
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5 Myths about Exercise and Sleep That Too Many People Still Believe
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