The Best Time of Day To Train for Metabolic Health

If you take your fitness seriously, you probably put a lot into planning your workouts and nailing your nutrition. You prepare mentally and want to get everything possible out of your efforts in the gym.

What if working out at a different time could get you better results?

Accumulating research shows that time of day has a major impact on an array of physical adaptations. One thing is becoming clear: Training in the late afternoon or early evening will produce greater strength, muscular, and metabolic adaptations.

Before we dig into the research, it’s worth mentioning that most important is that you get your workout in, regardless of the time of day. Many people don’t have the luxury of planning their training around their circadian rhythm, but for those who do, here’s what the research says.

Train In the Evening To Improve Metabolic Health

With the surge in obesity and diabetes, a lot of people are taking advantage of the potent therapeutic benefits of exercise for overcoming these health problems. New research shows that the time of day when you exercise can significantly impact the protective metabolic benefits of working out.

This study had active men eat an unhealthy high-fat diet (65 percent of energy from fat, 15 percent from carbs, and 20 percent from protein) for 5 days (1). After the initial dietary run-in period, they performed an exercise program, training in the morning at 6:30 am or in the evening at 6:30 pm for 5 days. Workouts alternated between a 20-minute high-intensity cycle workout and a longer 40-minute aerobic cardio workout.

Results showed that only exercise done in the evening was able to reverse the negative metabolic changes caused by the poor diet. The high-fat diet led to changes in how the body processes fats, especially LDL that is considered a risk factor cardiovascular disease. It also led to higher levels of triglycerides, which are fat circulating in the blood stream.

Evening exercise blunted the increase in LDL cholesterol and led to greater improvements in fasting glucose, insulin, and triglycerides. Evening exercise also dulled elevations in sphingolipids, which are inflammatory markers that promote hardening of the arteries and are a risk factor for cardiovascular disease.

Overnight blood glucose levels were also better in the group that did evening workouts. This is important because normally, blood sugar levels spike in the evening due to a decrease in insulin sensitivity and beta cell function. Counteracting this drop with evening training could help treat obesity and diabetes and may have implications for people who are trying to manage their weight.

Take Away:

Based on how it optimizes metabolism overnight, training in the evening may be your best bet for fat loss goals, and it can be a tool for protecting yourself from poor health, including, diabetes, cardiovascular disease, and metabolic-associated inflammation

Train In The Evening To Maximize Strength & Muscle

For performance that relies on the anaerobic system, such as lifting weights or sprinting, studies suggest performance is significantly greater in the mid-afternoon and early evening. In a 6-month study that compared strength and muscle gains in response to morning (between 6:30 and 10 am) and evening (between 4:30 and 8 pm) training, the group that exercised in the evening gained significantly more strength and muscle (2).

Maximal strength in the leg press increased by 13.2 percent more in the group that trained in the evening compared to the group that trained in the morning. Muscle gain was also greater in response to evening training with the evening group increasing cross sectional area of the quadriceps by 25 percent more than the morning group.

Scientists have identified at least three reasons for evening being prime time to train for strength and muscle:

First, body temperature is higher in the late afternoon and early evening, which heightens reaction time and the connection between the brain and muscle. Higher core body temperature improves nerve conduction velocity, joint mobility, and muscular blood flow. Plus, most people can achieve higher muscle activation in the evening when core temperature reaches its peak, which is why you are less likely to get injured but more likely to hit PRs.

Second, hormone levels tend to be optimal in the late afternoon. Most important is the ratio between testosterone and cortisol because recovery from exercise is faster when testosterone levels are higher and cortisol lower. Although testosterone peaks during the morning, it spikes in the late afternoon. Meanwhile cortisol output peaks in the early morning and curves downward over the course of the day, making early evening the time when the testosterone-to-cortisol ratio is highest. During this period, exercise causes the smallest rise in cortisol and the largest increase in testosterone (3, 4). Cortisol also recovers fastest after training later in the day.

Finally, protein synthesis peaks around 6 pm, which means that if you can train right before that, you’ll experience greater muscle growth and faster recovery. Protein synthesis is influenced by enzymatic reactions that are amplified by slight elevations in core body temperature. A better testosterone-to-cortisol ratio may also contribute to protein synthesis and muscle recovery.

Take Away:

Based on your peak in core temperature and the daily rhythm of your hormones, the best time to schedule training is between 3 and 6 pm for muscle, strength, and performance goals.

What If You Can’t Train In The Evening?

Don’t despair if you are not able to schedule your training at the physiologically optimal time. Exercise is enormously beneficial no matter when you do it. It’s worth experimenting with workout timing to see how it affects the work you get done during training and how you feel afterward.

For example, some people feel that morning training sets them up mentally and they like getting it out of the way so they can focus on other things during the day. Others rely on the stress relief they get from mid-day workouts during lunch. Or maybe you are so fatigued after work, that you are unable to drag yourself to the gym at 5 pm. In this case, you will get more out of your body by training earlier in the day. The key is to train at the time when it benefits you the most, whether that is performance feats, muscle growth, fat loss, or stress relief.