The Best Time of Day To Train For Muscle Growth

Introduction to Workout Timing.

This topic is for those who are more advanced lifters or interested in biohacking to optimize their natural physical abilities. What is the best time of day to workout for best results? Below we will discuss that in depth based on science, research, and my personal experience.

Why Consistency Matters for Muscle and Strength Gains

If you take your fitness seriously, you probably invest a lot of time planning your workouts and managing your nutrition. You prepare mentally and aim to maximize your efforts in the gym. But have you ever thought about how working out at a different time of day could potentially improve your results?

Numerous studies suggest that the time of day has a significant impact on various physical adaptations. It's becoming evident that training in the late afternoon or early evening leads to greater strength, muscle, and metabolic adaptations. Of course, it's essential to mention that the most crucial thing is to get your workout in, regardless of the time of day. Many people don't have the flexibility to plan their training around their circadian rhythm. However, for those who do, here's what the research suggests.

The Role of Circadian Rhythm in Exercise Performance

It's important to consider the states and hormone levels your body experiences during its 24-hour cycle, known as the circadian rhythm, to maximize the effectiveness of your workout sessions.

One aspect of this cycle is your sleep-wake pattern. It's often described as your "internal clock" because it regulates specific internal processes at different times of day and night, depending on light and darkness. Your lifestyle can disrupt and influence your circadian rhythm due to its connection with daylight and darkness. The circadian rhythm is most stable in individuals who follow a typical sleep schedule of 11 PM to 7 AM.

In addition to sleep, your circadian rhythm also regulates three other important factors for training: body temperature, energy metabolism, and levels of relevant hormones like testosterone and cortisol.

While you can benefit from working out at any time of the day, planning your sessions in accordance with your circadian rhythm can help you get the most out of your workouts. Science has extensively studied the effects of lifting weights in relation to our circadian rhythm. Creating an optimal workout schedule aligned with your circadian rhythm can help you get in shape more quickly, build strength, and potentially increase muscle gain while reducing the risk of injury during training at specific times of the day. For these reasons, it's crucial to pay attention when you work out. This article will delve into the scientific aspects of this issue and explore the pros and cons of working out during the three main times of the day.

Consider These 3 Factors When Deciding Whether To Work Out In The Morning or Evening.

The Testosterone and Cortisol Relationship

The ratio between testosterone and cortisol levels plays a crucial role in muscle building. Testosterone promotes muscle growth, while cortisol, a stress hormone, breaks down muscle tissue. These hormone levels naturally oscillate during the circadian cycle, with testosterone production peaking in the early part of the day and again in the evening, while cortisol levels are highest in the morning and decrease throughout the day. Exercise also influences these hormone levels.

There are multiple research studies done on this topic and one that comes to mind is based on Soviet Union strength athletes. This particular study has shown that there are two specific times of the day when the body's capacity to produce force and power is at its peak. The first peak occurs between 11:00 and 13:00, while the second peak (which is slightly smaller than the morning peak) occurs between 18:00 and 20:00. Additionally, athletes who train during one of these two periods tend to gain significantly more strength compared to those who train between 16:00 and 17:30. It's important to note that the first testosterone peak in your day is slightly higher than the evening one and provides a slight advantage to those trying to build strength, power and size. You can read more about this study in the book "Managing the Training of Weightlifters" by Laputin and Oleshko.

Many experienced coaches have emphasized that the optimal times for training are 3 and 11 hours after waking up. While the Soviet study did not specify the athletes' waking times, it likely aligns with a typical 7 or 8 am wake-up, suggesting that the best training times are 3-5 hours and 11-13 hours after waking up. This insight is consistent with the advice given by numerous coaches.

An Interesting and somewhat reliable test you can take to determine your testosterone peaks is by testing your hand grip using a handheld dynamometer every hour from when you wake up to just before going to sleep. Examine the 16 hourly charts to understand when you are most strong in your day and program your training around that period.

Core Body Temperature

It's important to keep in mind that your core body temperature fluctuates throughout the day, similar to your hormones. Maintaining an optimal temperature for your vital organs is crucial for peak performance and preventing injuries. A healthy circadian rhythm means that your core body temperature should be at its lowest during the night, rapidly increasing when you wake up, and reaching its peak in the evening.

Research, such as the study conducted at the University of the West of Scotland’s Department of Exercise and Sports Science, has shown that a higher core body temperature can enhance metabolism, muscular blood flow, joint mobility, and more. These factors are especially significant for strength training, as you'll be at your strongest and most flexible when your core body temperature is at its highest.

A low core temperature is one reason why strength exercises first thing in the morning (or within 1 hour of waking) are generally regarded as unsafe and potentially dangerous to your joints and in particular your back.

Here’s what Dr. Stuart McGill (PhD author of numerous articles on the spine) had to say on the subject: “As you know, you’re taller when you wake up in the morning than when you go to bed at night. This is because the discs are hydrophilic, that means they suck up water while you sleep and when there are no stresses present. After rising, hydrostatic stresses of just walking around and using the muscles during the day compress your spine, and the fluid is squeezed out, decreasing the annular tensions in the disc. So, when you wake up the extra height in the discs are analogous to a full water balloon ready to burst and if you bend, you build up much higher stresses in the disc. In fact, the stresses are three times higher than when you perform the same bend two or three hours later. I’m talking about heavy bending exercises, like for example the good-morning exercise or doing sit-ups. Somehow people thought that this would be a good thing to do in the morning. It’s the worst possible thing you could do for the back first thing in the morning."

Sufficient Nutrition

You can make an argument for both early and late training: when you train early in the day, you have the benefit of having several meals in the post-training period. This means you can have 3-5 meals during the post-workout period, which can support your recovery and energy replenishment.

On the other hand, if you train later in the day, you might only get to have 1 or 2 meals in the post-workout period, which may not be as optimal for recovery. On the other hand, if you train later in the day, you have a greater chance of being properly fueled for the session because you had more meals prior to the session. This could mean that you have more energy and nutrients available to support your performance during the workout.

The Pros and Cons of Morning, Afternoon, and Evening Workouts.

The Morning Workout (1 hour upon waking up)

PRO: Morning workouts lead to increased testosterone levels and heightened alertness. We've already covered the anabolic effects of testosterone, but being focused and alert also brings many advantages and boosts efficiency. Although most individuals are already alert in the morning, a workout can further enhance their focus and energy.

CON: Morning weight training has some downsides. It requires waking up earlier, so you need to plan ahead to avoid rushing to work, missing breakfast, or losing sleep. Exercising in the morning means you have higher cortisol levels and little to no food in your system, which can create a stressful internal environment for muscle building. This might impact your strength or strength-endurance as you are more likely to deplete your glycogen stores. 

DO: Lactic acid training as glycogen stores are lowest in the morning so take the opportunity to train with loads between 50% to 70% and incorporate supersets (2 exercises back to back) and giants sets (4 exercises completed as a circuit) to target fat burning most efficiently. Keep workout time below 45 minutes.

AVOID: Maximal strength or loads of 85% of 1RM (think 5 reps and below) as the internal core temperature is not sufficient enough to protect joints and ligaments from wear and tear. 

The Early Afternoon Workout (3-5 hours upon waking up)

PRO: Statistically, the afternoon is when the majority of the population is least active. This makes it a great opportunity to wake up your body with exercise without interruption from external stresses like work or emails and it can be a real sweet spot for many. Science shows that our pain tolerance seems to be the highest at this time of day, which can help push you harder during those workouts. 

It is also worth noting that protein synthesis peaks at roughly 6 pm, meaning that if you can finish your training in the hours before that, you’ll achieve better muscle growth and faster recovery which is amplified further by the better testosterone-to-cortisol ratio.

CON: Long exercise or training sessions (2 hours and above) with high caffeine content (spikes adrenaline and Cortisol further). Based on the research discussed earlier we know Cortisol is around 50% lower at this time vs the morning when it's highest. Raising it back up to 100% levels means the majority of your day will be spent in an elevated cortisol state breaking down vital muscles.

DO: Maximal strength as testosterone peaks highest at this time of the day based on the studies we looked at earlier, so it's best to train with loads 85% and above (5RM and below). Internal core temperature is optimal to handle heavy loads with minimal risk compared to morning sessions.

AVOID: Nothing really. Hormones and core temperature are all fairly balanced by this point. You could train multiple energy systems at this point with effective results.

The Evening Workout (11-13 hours upon waking up)

PRO: Training late provides the advantage of having a sufficient amount of fuel and nutrients in your body provided you've already eaten 4-5 meals prior to the training session to maximize workout performance. 

Overnight blood glucose levels were also better based on studies that had individuals working out in the evening. Why is this important? Well, typically blood sugar levels spike in the evening due to decreased insulin sensitivity and beta cell function. By training in the evening you counteract this drop which can benefit those who suffer from obesity and diabetes or people who are trying to manage their weight and fat loss goals.

CON: I don't recommend training in the evening at all unless you must as it reintroduces high cortisol levels back in the body again which can disturb the circadian rhythm (cortisol should be high in the morning and low in the evening). There is a much higher chance of adrenal fatigue with evening sessions due to your heart rate becoming elevated longer when your body is trying to wind down and your overall time under REM sleep is drastically impacted affecting deep sleep where the real recovery happens.

DO: Hypertrophy style training with loads between 65% - 80% (between 7 - 12 reps). Rest periods should be kept between 60-90 seconds, and workouts below 75 minutes, after this point cortisol spikes dramatically.

AVOID: While the research also suggests there is a second peak of testosterone in the evening, I recommend avoiding hard training or maximal strength with loads of 85% of 1RM (think 5 reps and below). I believe it activates the nervous system too much before bed making it difficult to sleep or get into a deep REM cycle which is critical in providing quality sleep and recovering.

Conclusion: Is it better to lift weights in the morning or at night?

Both options can work depending on the individual and their goals. The most important factors are prioritizing a consistent training schedule, maintaining a healthy diet, and ensuring you get enough quality sleep. While new research may provide more insights in time, for now, focusing on these aspects is likely to have the strongest impact on your workout performance and muscle gain. It's worth noting that our body's natural rhythms vary, so it's important to adapt your training schedule to fit in with your work, leisure, and sleep patterns. Your body tells you best - for example, I believe some are natural ascenders and descenders. Ascenders wake up with less energy, and their energy levels typically rise throughout the day while descenders wake up with more energy that naturally goes down throughout the day.

The Physique Protocol Pro Tip

In a perfect world, the best time to workout would be 3-5 hours upon waking. A close second would be 12-13 hours upon waking although soviet union athlete research showed this being about 10% less effective than the 3-5 hour window.

So essentially...

The absolute best time to train is: 3-4 hours upon waking

A good time to train is: 12-13 hours upon waking

An extended effective training zone would be: 2 to 5 hours upon waking and 12 to 14 hours upon waking

“The no other choice” zone: 1 hour upon waking and 6 to 8 hours upon waking

“Avoid if maximum results don't concern you” zone: less than 1 hour upon waking, 9 to 11 hours upon waking, and 15 or more hours upon waking