In the era of social media fitness influencers, muscles have become highly-prized fashion accessories. However, they are much more important than that. Our muscles are metabolic organs that play a wide range of functions far beyond impressing friends and colleagues.

For instance, muscles are energy-hungry tissue, and, as such, they store glucose. This means that having a healthy level of muscle mass helps keep blood sugar levels more stable.

Also, as we age, maintaining muscle mass becomes extra important. Older adults with significant muscle loss (sarcopenia) are more likely to experience falls and develop frailty sooner.

Muscles also contribute to the negative health outcomes of obesity. Often, people with obesity, while gaining body fat, also lose muscle and muscle quality.

This can create a spiral of decline: Time spent sedentary is associated with a loss of muscle and weight gain; the loss of muscle then makes physical activity more difficult.

We all have a biological clock, known as our circadian rhythm. It helps us feel sleepy before bed and wake up feeling refreshed. Every cell in our body runs on a roughly 24-hour schedule to keep us aligned with the natural light-day cycle.

However, how aligned individuals are with this cycle varies. Some go to bed early and wake early (larks), others go to bed late and stay awake late into the evening (night owls), and everyone else is somewhere in between.

Our chronotype also impacts how effective training is at different times of day. Larks tend to have their best physical performance in the early afternoon, while night owls perform best in the late afternoon or evening.

According to the authors of the new paper, being a night owl is “consistently associated with poorer sleep, irregular eating habits, reduced physical activity, and increased risk of obesity, sarcopenia, and metabolic disorders compared to morning types.”

They tackle night owls’ potential issues with nutrition, sleep, and exercise in turn.

Nutrition tips for a night owl

High fat diets, the authors explain, can upset circadian rhythms. In turn, this can lead to insulin resistance, inflammation, and imbalances in hormones that are important for appetite signaling, like leptin and adiponectin.

Research also shows that meal timing is important. For instance, the authors of the review explain that the timing of the largest meal of the day is probably important.

Night owls could benefit, they suggest, from shifting their largest meal to an earlier time in the day, rather than the evening.

Sleep quality for night owls

Perhaps surprisingly, sleep plays a role in muscle health. The authors explain that specific hormones, which support muscle growth and prevent muscle breakdown are partly driven by metabolic processes that are influenced by circadian rhythms.

Lack of sleep also negatively affects muscle health by interfering with blood glucose (sugar) control and, once again, disrupting hormones involved in appetite control, while boosting stress hormones such as cortisol.

These changes reduce muscle protein synthesis, leading to muscle loss, weakness, and poorer physical function.

The authors suggest that: “To support muscle health, adults should maintain a regular sleep-wake schedule, avoid late-night training and screen exposure, and consume protein-rich meals earlier in the evening to enhance overnight recovery.”

Exercises for an evening chronotype

Exercise not only influences circadian rhythms, but it also plays a pivotal role in muscle growth and strength. As mentioned earlier, muscles play important metabolic roles throughout the life course.

Exercise timing also matters, especially for night owls. Studies suggest that training in the afternoon or evening is associated with greater muscle growth, while morning training supports mitochondrial health and cellular housekeeping.

While questions remain, the scientists also outline complex interactions between exercise and genes that help regulate the circadian clock. These relationships suggest that matching exercise timing with the body’s natural rhythms might improve muscle adaptation, performance, and long-term health.

“The main objective is for people to be active and avoid a sedentary lifestyle,” Pablo M. Garcia-Rovés, MD, a member of the MitoHealth research group, explained in the press release.

“[A] better understanding of their characteristics and habits allows for the design of more precise interventions that contribute to improving the health and functionality of the population. This approach may be particularly relevant in a society with irregular schedules and a progressively aging population.”
— Pablo M. Garcia-Rovés, MD

Medical News Today contacted two fitness experts to ask for their advice for individuals with a late chronotype on how to get in shape and maintain health.

“If you’re an evening type, try shifting your main meals to earlier in the day to match your body’s natural rhythms,” suggested Denise Chakoian, a Rhode Island Certified Fitness Trainer and owner of Core Cycle and Fitness LaGree. Chakoian was not involved in the recent paper.

“Prioritize protein at each meal to help build and maintain muscle. Aim for consistent, good-quality sleep to support recovery and hormone balance,” Chakoian added.

She also recommended planning workouts later in the afternoon or early evening “when your energy and strength are naturally higher.” Chakoian further recommended avoiding eating just before bed, “as late-night calories can increase fat storage and hurt muscle growth.”

‘Work with your biology’

Stephen Sheehan, a certified personal trainer with Garage Gym Reviews who was likewise not involved in the study, suggested that night owls should “work with their biology.”

He explained that many evening types believe they have to change everything to see results: wake up before dawn and completely adjust their typical schedule.

“That almost always backfires,” he told MNT, “because it’s an all-or-nothing approach, which studies show can easily derail a workout program or other attempts at lifestyle change.”

Instead, Sheehan suggested night owls should “completely ditch the idea that they need to slam weights pre-dawn, and lean into what’s natural for their body.” This removes the mental barrier and “improves the quality of training.”

As for food, in line with the review paper, he recommended “moving mealtimes earlier in the day, particularly one’s highest-calorie meal of the day. This could positively affect health markers like fat-free mass index and body mass index (BMI), thereby positively influencing metabolic health.”

Overall, Sheehan suggested following these basic principles:

• Don’t force yourself to wake up early to train.
• Try to train between 4 and 8 p.m.
• Keep a buffer of 2 hours between the end of your training session and bedtime.
• Eat your highest-calorie meal sometime before training, not after.
• Get 70% of your day’s protein in before training.

He also recommended people “Find a relaxing hobby that can take the place of scrolling on your phone or watching TV before bed. Try reading, writing, knitting, coloring, building legos — whatever. Anything that isn’t shining a blue light in your face. Bonus points if it’s something creative (cognitive health is important, too).”