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Purpose Of The Study
The purpose of this study was to determine how the timing of resistance training may influence how you sleep in terms of quality, latency (how long it takes you to actually fall asleep) and how long you sleep. Additionally, the researchers wanted to observe changes of nighttime blood pressure, as poor sleep quality and duration may be associated with ailments such as cardiovascular disease, diabetes, and obesity (1).
Why Study This
For starters, some research indicates that up to 30% of adults experience some form of insomnia. There is also some research to suggest that resistance training may be beneficial for improving sleep quality and other sleep related metrics. If improved sleep is one of the benefits you receive from resistance training, understanding when to exercise based on the side effect you need may be quite helpful. Not to mention, it's cool to see that the time that you exercise can actually influence your sleep. The body is truly amazing (2).
It's important to remember that while this was a fairly standard bodybuilding approach, results from other styles of training. For example, another very similar study from the same laboratory tested all of this using cardio exercise as well. With their findings, other time points had different effects...So while this may have been a bodybuilding study, it's important to remember that training with a different style of exercise may produce drastically different results.
Subjects between the ages of 18-25 were recruited from Appalachian State University to take part in this study. Subjects included in this study were either sedentary or recreationally active. Note, it's important to remember that these were fairly untrained individuals. Responses observed in this study may different from the responses that a trained individual would experience.
During the first visit, subjects were exposed to a 10RM test protocol, using 9 different exercises including:
Subjects were randomly assigned to a training group. All groups completed exercises by using 65% of their tested 10RM for 3 sets of 10 repetitions each. Subjects were assigned to train at either:
Following resistance training, subjects used a headband sleep monitor, which measured sleep architecture and blood pressure to evaluate the effect of each resistance training protocol on sleep.
Essentially, all subjects completed the same training protocol: 3 x 10 with 65% of their 10RM. They either trained at 7 am, 1 pm or 7 pm. After that, they had sleep monitored to observe if and how each training time affected sleep. Keep in mind, there are some very important considerations that we'll dive into shortly.
Results Are Far From Conclusive
Studies like this are quite difficult to draw definitive conclusions from. Any number of variables could be influencing sleep, so it's difficult to determine how much of an effect resistance training really did have on these subject's ability to sleep. According to changes from the control measurements, it does seem that there was an effect of resistance training and further, that the time of day exercise was completed influenced which side effect was experienced.
Sleeping Was Done At Home
Typically in a study like this, subjects would sleep on site, in order for researchers to evaluate throughout the night. In this study, subjects slept at home and self administered the sleep monitor. The researchers chalk this up to a beneficial point, since sleeping in a laboratory or an unfamiliar environment, could negatively influence the subject's ability to sleep well or even at all.
Personally, I view this as a confounding factor because there are any number of variables that could go wrong. For instance the headband could come off. In a lab setting, a technician could notice a malfunction and correct it immediately. When the subject administers the test at home, the researchers have no way of knowing what actually happens.
These Were College Kids
These were college kids, instructed to refrain from caffeine and alcohol, both of which negatively influence sleep. I'll let you decide for yourself if college students 1: refrained from caffeine and alcohol and 2: followed protocol exactly.
Changes Are On Average
Certainly there was benefit of resistance training, regardless of time. But it's difficult to pinpoint that a specific time of training might have a specific result. It's likely that each individual person would respond individually to certain time points of training.
You have to remember that each person has an individual rhythm of responses to any number of stimuli. Each individual could have a different response to the time in which they exercise. I suggest trying out training at different time points and then observing how each affects your sleep patterns.
Different Training Styles May Change The Response
It's important to remember that while this was a fairly standard bodybuilding approach, results from other styles of training. For example, another very similar study from the same laboratory tested all of this using cardio exercise as well. With their findings, other time points had different effects. For example in the cardio study, training at 7AM using cardio was more effective at reducing time awake after awakenings. This is different from the resistance training study where the 7 pm group reduced awakening time the most (3).
So while this may have been a bodybuilding study, it's important to remember that training with a different style of exercise may produce drastically different results.
Essentially, if you have difficulty sleeping and don't exercise, adding a resistance training or aerobic exercise routine to your schedule may have a significant impact on your ability to sleep. Further, adjusting the time in which you train may provide a different response, such as time to sleep onset or times awoken during the night. I suggest first adding exercise into your routine and then adjusting the time point of that training session to see which works best for you.
If you already train and still have trouble sleeping, it may be in your best interest to explore different training time points, based on your ailment and schedule.
It's important to remember though that the style of training you use may have significantly different responses from another.
Why This Should Matter To You
It should matter because some research reports that up to 30% of adults suffer from insomnia. This research suggests that exercise can significantly influence sleep properties, which may help many people that don't exercise for one reason or another. In a world where everyone takes a pill for their issues, this research shines light on a naturally, often free alternative for improving sleep issues.
A Little Extra Advices
I’ve come to realize in the past couple of years that sleep is of the utmost importance. Because of this, I personally take supplements to help with my sleep. However, I’ve chosen only a couple things to help because they are backed by sound research and are also thought to not cause dependency. My current sleep stack along with why is as follows:
~10 mg of melatonin
~5 g Taurine