The Bottom Line:
Here is a summary of the main points in the format you requested:
- Our bodies have an internal clock that affects our readiness to train throughout the day, with strength peaking around 6 pm due to circadian rhythms and body temperature fluctuations.
- A meta-analysis found that while people are slightly stronger in the evening, there were no significant differences in strength gains between morning and evening training groups, except for a small effect favoring evening training when strength was tested in the evening.
- The same meta-analysis found no differences in muscle growth between morning and evening training groups, indicating that training time likely doesn’t significantly impact hypertrophy.
- Mechanistic rationales don’t always translate to practical outcomes, so it’s important to look at studies measuring the actual results you’re interested in rather than relying solely on isolated mechanisms.
- For most people, the best time to train is whenever fits your schedule, but athletes with evening competitions may benefit slightly from consistently training in the evenings.
The Role of Circadian Rhythms in Training Performance
Understanding Circadian Rhythms
Circadian rhythms are the body’s internal clock that regulates various physiological processes, including hormone secretion, body temperature, and sleep-wake cycles. These rhythms are influenced by external cues such as light and darkness, as well as internal factors like genetics and age. The circadian system plays a crucial role in determining an individual’s readiness to train and perform physical activities throughout the day.
Research has shown that strength and power output tend to peak in the late afternoon and early evening, coinciding with the highest point of core body temperature. This suggests that the body’s natural circadian rhythms may predispose individuals to perform better during these times. However, it is important to note that these fluctuations in performance are primarily attributed to peripheral mechanisms at the muscular level rather than central nervous system factors.
Circadian Rhythms and Training Adaptations
While circadian rhythms can influence acute performance, their impact on long-term training adaptations is less clear. Some studies have compared the effects of morning versus evening training on strength and muscle growth, with mixed results. A meta-analysis by Grgic and colleagues (2018) found that while individuals may exhibit slightly greater strength in the evening, there were no significant differences in strength gains between morning and evening training groups over time.
Interestingly, the meta-analysis did suggest some specificity to training time and strength improvements. Participants who consistently trained in the evening showed greater strength gains when tested in the evening compared to those who trained in the morning. However, this effect was small and did not extend to morning strength assessments or measures of maximum voluntary contraction force.
Practical Implications for Training
Despite the potential influence of circadian rhythms on acute performance, the time of day at which an individual trains likely has minimal impact on long-term muscle growth. This is good news for those who have limited flexibility in their training schedules due to work or other commitments. Whether you train in the morning or evening, you can still optimize your muscle-building progress by consistently adhering to a well-designed training program and proper nutrition.
For athletes who compete in events that typically take place in the evening, there may be some benefit to consistently training at that time of day. By aligning their training with their competition schedule, athletes may experience slight improvements in performance due to the specific adaptations gained from training at the same time as their events.
Strength Peaks in the Evening: Examining the Evidence
Examining the Evidence for Evening Strength Peaks
Several studies have investigated the potential differences in strength performance at various times throughout the day. A study by Guette and colleagues (2005) assessed knee extensor strength at 6 a.m., 10 a.m., 2 p.m., 6 p.m., and 10 p.m. The results showed that strength peaked at 6 p.m., suggesting that muscles may be primed for optimal performance in the evening. This peak in strength coincided with a peak in core body temperature at 6:15 p.m., indicating that circadian rhythms may play a role in predisposing individuals to perform best around this time. Interestingly, the increase in performance was primarily attributed to peripheral mechanisms at the muscular level rather than central nervous system factors.
Meta-Analysis: Morning vs. Evening Training for Muscle Growth
To further investigate the impact of training time on muscle growth, Grgic and colleagues (2018) conducted a meta-analysis of 11 studies that compared morning and evening training groups. These studies ensured that both groups performed the same training program, allowing for the isolation of the time-of-day variable. While all 11 studies measured strength outcomes, only five examined muscle growth specifically.
The meta-analysis revealed that participants were slightly stronger in the evening compared to the morning at baseline, before engaging in the training programs. However, when assessing strength gains from pre- to post-study, no significant differences were found between the morning and evening training groups when strength was tested in the morning. When strength was assessed in the evening, the evening training group did show slightly greater gains compared to the morning group, suggesting some specificity to training time and strength improvements across the day. Notably, this effect was small and only applied to evening training.
Practical Implications and Takeaways
Despite the mechanistic rationale for potential differences in strength and muscle growth based on training time, the meta-analysis by Grgic and colleagues (2018) found no significant differences in muscle hypertrophy between morning and evening training groups. This finding is particularly important for individuals with busy schedules who may only have the opportunity to train in the morning due to work or other commitments. The evidence suggests that training time does not significantly impact muscle growth, allowing for flexibility in scheduling workouts.
However, for athletes who compete in events that typically take place in the evening, consistently training in the evening may provide a slight performance advantage. By aligning training time with competition time, athletes may be able to optimize their progress and performance in those specific events.
Comparing Morning and Evening Training for Muscle Growth
Examining the Impact of Training Time on Strength and Hypertrophy
Several studies have compared the effects of morning and evening training on strength and muscle growth. A meta-analysis by Grgic and colleagues in 2018 included 11 studies that compared two groups performing the same training program, with one group training in the morning and the other in the evening. While all 11 studies measured strength outcomes, only five examined muscle growth.
The meta-analysis found that participants were slightly stronger in the evening compared to the morning at baseline, before beginning the training programs. However, when assessing strength gains from pre- to post-study, no significant differences were observed between the morning and evening training groups when strength was tested in the morning. Interestingly, when strength was assessed in the evening, the group that trained in the evening demonstrated greater strength gains compared to the morning training group, albeit with a small effect size.
The Role of Circadian Rhythm in Training Performance
The body’s internal clock, or circadian rhythm, plays a role in determining readiness to train throughout the day. A study by Guette and colleagues in 2005 found that knee extensor strength peaked at 6:00 p.m. compared to other times of day, such as 6:00 a.m., 10:00 a.m., 2:00 p.m., and 10:00 p.m. This peak in strength coincided with a peak in core body temperature at 6:15 p.m., suggesting that the circadian rhythm predisposes individuals to perform best around this time.
The increase in performance was primarily attributed to peripheral mechanisms at the muscular level rather than central nervous system factors. The idea is that by training at the optimal time each day, individuals may perform slightly better in each session, leading to an increased stimulus and, ultimately, more muscle growth in the long term.
Practical Implications and Takeaways
While the mechanistic rationale for training at a specific time of day may seem compelling, it is essential to consider the practical implications and the actual evidence regarding muscle growth. The meta-analysis by Grgic and colleagues found no significant differences in hypertrophy between participants who trained in the morning versus those who trained in the evening.
This finding is encouraging for individuals with busy schedules who may not have the flexibility to train at a specific time of day. Whether you train in the morning or evening, you can still optimize your muscle-building potential. However, for athletes who compete in the evening, consistently training in the evening may lead to slightly better performance in competitions.
Practical Takeaways: Optimizing Your Training Schedule
Finding Your Optimal Training Time
While the research suggests that training time may not significantly impact muscle growth, it’s still important to find a training schedule that works best for you. Consider your daily routine, work schedule, and personal preferences when deciding on a training time. Some individuals may feel more energized and motivated to train in the morning, while others may prefer evening workouts. Experiment with different training times to determine when you feel most comfortable and can consistently adhere to your workout plan.
Consistency is Key
Regardless of whether you choose to train in the morning or evening, the most crucial factor in optimizing your training schedule is consistency. Stick to a regular training routine that allows you to maintain a balanced lifestyle while still prioritizing your fitness goals. Aim to train at the same time each day, as this can help establish a habit and make it easier to stay committed to your workouts. Remember, the best training schedule is the one you can sustain long-term.
Tailoring Your Training for Specific Goals
While the overall impact of training time on muscle growth may be minimal, there are certain situations where tailoring your training schedule can be beneficial. For example, if you’re an athlete preparing for evening competitions, consistently training in the evening may help optimize your performance during those events. Similarly, if you have specific strength goals, training at a time when you feel most energized and capable of lifting heavier weights may be advantageous. However, for the majority of individuals focused on general muscle growth and fitness, training time is less critical than factors such as exercise selection, progressive overload, and proper nutrition.
Specific Considerations for Athletes and Competition Timing
Timing Considerations for Competitive Athletes
For athletes who participate in competitions, the timing of their training sessions can have a significant impact on their performance. Studies have shown that athletes tend to perform better in the evening compared to the morning, particularly when it comes to strength and power-based activities. This is likely due to the body’s natural circadian rhythm, which results in peak muscle strength and power output in the late afternoon and early evening.
As such, athletes who consistently train in the evening may see slightly better performance gains compared to those who train in the morning. This is especially true for athletes who compete in events that take place in the evening, such as track and field meets or weightlifting competitions. By training at the same time of day as their competitions, athletes can help to optimize their performance and maximize their chances of success.
Practical Implications for Athletes
While the research suggests that training in the evening may be slightly more beneficial for competitive athletes, it’s important to keep in mind that the differences in performance gains between morning and evening training are relatively small. As such, athletes should prioritize consistency and adherence to their training program above all else, regardless of the time of day they choose to train.
That being said, athletes who do have the flexibility to train in the evening may want to consider doing so, particularly if their competitions take place later in the day. This can help to ensure that their bodies are primed and ready to perform at their best when it matters most.
Balancing Training with Other Commitments
Of course, for many athletes, training in the evening may not always be feasible due to work, school, or other commitments. In these cases, it’s important to find a training schedule that works best for their individual needs and circumstances. Whether that means training early in the morning, during their lunch break, or at some other time during the day, the key is to be consistent and to prioritize their training as much as possible.
Ultimately, while the timing of training sessions can have an impact on performance, it’s just one of many factors that athletes need to consider when developing their training plan. By working with a qualified coach or sports scientist, athletes can develop a customized training program that takes into account their individual goals, preferences, and lifestyle factors, helping them to optimize their performance and reach their full potential.
