What’s the best time to work out? The short answer: It depends.
I’m currently in that awkward transition between switching from evening workouts to morning, and I’m not going to lie, it hasn’t been easy. Every morning I’m now surrounded by people who seem to have much more energy than me, even though I slept pretty well.
Personally, it takes much more effort to prep and ready my body for a morning lift compared to my normal evening bouts. Of course, physically I anticipated this aspect (I just slept, the body needs a longer warm-up), but the mental energy levels is what’s really been the struggle. As a coach, I already understood much of the reasoning for my physiological adaptations, but I wanted to dive deeper and see what studies have shown before on this topic.
This article will dive into what factors influence the time of day you workout, what the scientific literature has shown, and how to choose your perfect time.
Factors that Influence AM and PM Workouts
There are multiple factors that are going to play a role in when your body will respond best to physical stress, aka moving weight. A lot of them are completely natural within the body, while some depend on your daily habits.
- Circadian Rhythm: This is our body’s natural 24-hour clock. It’s endogenous for the most part (runs internally), but factors like temperature, sunlight, and other external cues can influence it. Our rhythm will play a role in how awake we feel, which will then influence different levels of hormones, energy, and other factors.
- Hormone Levels: This factor plays off our circadian rhythm and will differ slightly between individuals, but is relatively consistent when unaltered. For example, our natural testosterone levels tend to be higher in the am hours and taper as the day goes by, but this can differ from individual to individual.
- Energy Stores: How we produce energy can also play a role in the time we workout. For example, glycogen levels (one of our go-to forms of stored energy) are lower in the morning, this is why folks often recommend doing cardio in the a.m. for fat loss, but it can also leave you feeling groggy when it comes to strength movements.
- Body’s Temperature: As the day progresses your body’s temperature will rise and regulate more thoroughly. The colder your body is, the stiffer and slower you may feel, which can play a role in your performance.
- Reaction Time (Neural Influence): Our nervous system progressively becomes more stimulated as the day goes on. For this reason, our reaction time has been seen to be higher in the afternoon hours (could play a role in power-based movements).
- Stress: Our stress levels can play a role in choosing the perfect workout time too. A lot of folks find themselves progressively more stressed as the day goes on, so their workout can take a hit.
- Time Allotment: Simple question: When do you have the time in your schedule for a full workout?
What Science Suggests About the Time of Your Workout
Does science have a definitive answer for the perfect workout time? No, it would be nearly impossible to do so due to the vast amount of workout styles and athletes out there. But there have been a plethora of educated suggestions made on optimal times based off the above factors.
Benefits of Morning Workouts
Sleep Quality: A study performed in 2014 compared individuals who worked out at three different times during the day: 7 am, 1 pm, and 7 pm. The study utilized 20 subjects between the ages of 30-60 years old with pre-hypertensive blood pressure. Each subject performed a 30-minute bout of moderate exercise on a treadmill that equated to 65% of their VO2 Peak.
Researchers found that those who worked out at 7 am slept better and woke up less frequently throughout the night. Additionally, they had a lower recorded mean blood pressure as they slept when compared to their afternoon counters.
[Early riser? Check out the 12 Things All Morning Exercisers Do, But Won’t Admit To; how many can you check off?]
Fat Burn: As mentioned above, glycogen stores are lower in the morning, so there may be a slight fat burning advantage to morning workouts. A study from 2013 analyzed 12 physically active males and compared them in four ways. The first two groups consisted of subjects who worked out in the morning fasted and then with a breakfast, and the other two groups fasted and had breakfast without a workout.
[How beneficial is breakfast for your strength and fat loss? This article dives into the science and explanation behind what breakfast can do, and cannot do.]
Their research suggested that those who worked out in the am, whether it be fasted or fed with exercise had curbed appetites throughout the day. They suggest that a fasted workout may have some impact in total daily energy consumption, which is beneficial if fat loss is your goal.
Benefits of Evening Workouts
Performance: A study from 2014 compared nine recreational cyclists who performed tests at either 8 am or 6 pm. The subjects performed each cycling bout after either a morning fast, or 6-hour fast prior to 6 pm. Researchers looked at multiple aspects such as subject’s power output, aerobic power, anaerobic power, EMG, oxygen uptake, and heart rate.
Their results made a few suggestions based on the time of each subject’s performance. They found that those who tested in the evening had a lower timed trial (aka better 1,000-m performance), higher power output, higher anaerobic power output, slightly higher aerobic power output, and slightly higher heart rate. EMG and VO2 levels were similar in both morning and evening subjects.
Power Output: Another 2014 study found similar results to the study listed above. Researchers compared 16 elite rugby player’s core temperatures and lower body power outputs (measured by counter jump movements) in both the AM and PM. Subjects performed the counter jump tests in the same day.
Researchers noted that as the day progressed, so did one’s core temperature, which has been documented to play a role in muscle contraction, power output, and performance. They found that as an athlete’s temperature got higher as the day progressed, so did their lower body power output.
[Want to try a new modality to increase power? Check out this article that dives into the science and usefulness of adding resistance bands to your movements.]
Does It Really Matter?
Not so much. A review from from 2012 compared multiple studies that analyzed performance factors in both the morning and evening (it’s long, but worth the read if you’re interested). The authors broke down each study and compared what they suggested to be best. They looked at aerobic performance, resistance training, time of day when tapering, and many other variables.
They document that multiple studies display varied results, but there tends to be a common denominator and that’s individual adaptation to the time of day you workout. Basically, as you consistently workout at a certain time, your body’s circadian rhythm will adapt (among other factors), which will benefit your performance. The key is time consistency.
How to Choose What Workout Time Is Best For You
The studies shared above are only a few examples of what research has dove into when it comes to different times of day and working out. What’s more important is finding what works best for you. Before making the switch from evening to morning workouts I asked myself three questions based off of the factors listed above.
- At what time of day do I have the right amount of time to warm-up properly and cool-down accordingly? How I answered: Morning, I can go early and get to work at a consistent time.
- When am I most stressed and drained mentally/physically? How I answerd: I’m most drained in evenings after long days.
- When do I often have the most natural energy? How I answered: Mornings.
I hate feeling rushed when I work out, or drained for that matter, so it was a no brainer when I sat down and analyzed what time of day would work best for my schedule. Getting off work inconsistently and having stress filled days kills evening workouts.
Steps to Improve Your Perfect Workout Time
When it comes down to what will work best for you, it’s more so dependent on your preferences/schedule allowance. The review posted above suggests that our body’s can adapt to any time when it comes to working out, and the key is consistency. Below are a few suggestions on how to make your perfect workout time of day flow better.
- Set a Time Frame: I wrote a 6-week program for my morning workout transition. The above studies (specifically in the review), displayed that after 6-weeks of consistently timed workouts that the body began to adapt and improve performance. Give it time.
- Create a Routine: I’ve almost got my morning down to a routine, as in, I wake up, drink a cup of water, eat two eggs with ½ cup of oats, and then I’m good on energy and hunger, but not too full. It took me a week of experimenting with my morning rituals and a morning meal routine for optimal energy, but I’m finally nailing it. Experiment with different aspects like this to improve your personal performance.
- Write It Down: After each workout I write down three things. One, how hard the lift felt compared to previous days. Two, my energy levels. Three, things I did before the workout that may have played a role in my performance.
- Plan B Options: Everyone should have a backup plan when things don’t go accordingly. This could be a workout you keep in your back pocket when you’re feeling extra drained, or a snack/drink/supplement that you reach to when energy is really low. If I’m randomly drained or crunched for time, I drop my volume of my workout to 65%, but keep the intensity the same. This way I’m still achieving a stimulus, and making progress to an extent, but saving my nervous system and keeping stress relatively low. Plus, it’s easier to grind out a workout this way.
The time of day you work out can play a role in your performance, and it’s a much more loaded question than most make it out to be. When it comes to finding what’s best for you, plan around your schedule and personal preferences.
Science suggests we can adapt to multiple times, so don’t feel limited or pressured into thinking one time is better than the other.
Feature image screenshot from @brookeence Instagram page.