Do you work out as soon as you awaken in the morning? No doubt about it, a sweat session is invigorating and gets you prepared for the upcoming day. Plus, it energizes you mentally and physically so you can tackle the daily challenges that lie ahead. Yet, there are advantages to exercising later in the day as well. Working out after work helps clear your mind and relieve the stress and tension that inevitably builds up over the course of the day. Even if you feel too tired to do it, once you start you feel that magical surge of energy. But what about strength training? Will you get better results if you strength train at a certain time of day? Morning or evening – does it matter?
Building Strength – Does Time of Day Matter?
Although few studies have looked at whether you gain more strength if you work out at a particular time of day, we can get insights by looking at how your body functions. You have an internal biological clock that determines your body’s circadian rhythms, the natural ebb and flow of hormone release, blood pressure regulation, and other physiological processes that your body carries out on a 24-hour basis. There’s even a portion of your brain dedicated to setting your biological clock – it’s called the suprachiasmatic nucleus.
How does this essential clock function? The suprachiasmatic nucleus is sensitive to environmental cues such as light coming into your eyes. The rays then strike the light-sensitive tissue in the back of your eyes called the retina. It uses light to set your clock so you’re in sync with the outside world. Not getting enough sleep or sleep at irregular hours can alter your biological clock and your body’s natural rhythms. Unfortunately, disruption of these rhythms is linked with health issues, such as a higher risk of type 2 diabetes and even cancer.
What does this have to do with strength training? Based on the rhythms set by your biological clock, physiological functions vary depending on the time of day. For example, your body temperature is lowest at around 4:30 A.M. when you’re probably still sleeping. Your body temperature gradually rises upon arising and throughout the day and typically reaches a peak at around 7:00 P.M.
Based strictly on body temperature, strength training first thing in the morning would not be optimal. Just after awakening, your body temperature is close to its lowest point. How supple can you expect your muscles to be when you first get out of bed? Muscle flexibility is at an all-time low when you first awaken. Low body temperature and less supple muscles also increase the risk of injury.
Muscle Protein Synthesis
Does muscle protein synthesis vary by time of day? To build muscle, you need to repair damaged muscle fibers sustained during a workout and enhance the size of the existing muscle fibers by building new contractile elements. According to some research, muscle recovery and the rate of muscle protein synthesis is greatest in the late afternoon and early evening. Will training at this time translate into greater gains in muscle or strength?
A study published in the Journal of Strength and Conditioning Research found no significant difference in muscle hypertrophy gains when healthy men trained in the morning and opposed to the afternoon over a 20-week period. But, another study involving healthy, strength trained guys found that those who trained in the evening (after 6:00 P.M.) gained 3% muscle size and lost 4% body fat, while the guys that worked out before 6:00 A.M, lost no body fat and gained only a small amount of muscle.
What about hormonal variations? We know that certain hormones, particularly testosterone, are anabolic and promote muscle hypertrophy. Testosterone reaches its peak in the morning. This might suggest that strength training in the morning would be advantageous due to the favorable anabolic effects. However, the stress hormone cortisol also peaks after your first wake up Cortisol is a catabolic hormone that opposes the action of testosterone by stimulating the breakdown of muscle tissue. So, you have two opposing forces, one anabolic and one catabolic. Do they cancel out? It would seem likely.
You’re Stronger Later in the Day
How strong do you feel when you wake up in the morning? If you’re like most people, you don’t feel like grabbing a heavy dumbbell when you first wake up and you may even feel a bit stiff. It’s not your imagination. Not only are you less flexible in the morning but your strength is at a nadir. Strength typically reaches a peak in the early evening. If you work out in the morning, you may not push as hard as in the evening when your muscles are warm, supple, and at your strength is peaking.
Coordination and reaction time are also greater in the afternoon as opposed to the morning. Plus, pain tolerance is higher in the late afternoon and early evening relative to the morning. With strength being high and pain tolerance also being high, you might be able to push more weight if you train later in the day. As a general rule, athletes perform best in the late afternoon and early evening.
One downside to lifting late in the day is the fatigue and motivation factor. After a long day at work, your motivation to push yourself may be lower. Therefore, a workout after work may be less productive. Of course, this depends on the hours you work and the type of job you have. If you sit all day, a weight training workout might be just what you need to perk up.
The Bottom Line
Although the time that’s best for weight training varies with the individual, based on time alone, weight training in the afternoon seems to offer the best balance. Your muscles are stronger and more flexible than they are first thing in the morning and your energy and motivation will likely be higher. This doesn’t mean you shouldn’t exercise in the morning. A circuit workout using lighter weights and cardiovascular drills can boost your energy level so you can better take on the day. However, when you’re doing serious strength training with heavy weights, afternoon or early evening training has advantages. Ultimately, you might be forced to decide based on your schedule. Whichever you choose, warm up thoroughly beforehand.
J Nutr. 2016 Jul;146(7):1307-14. doi: 10.3945/jn.116.230086. Epub 2016 Jun 8.
Bodybuilding.com. “What Is The Best Time Of Day To Weight Train?”
J Strength Cond Res. 2009 Dec;23(9):2451-7. doi: 10.1519/JSC.0b013e3181bb7388.
Prozis.com. “What’s the best time of the day to work out?”
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