Rarely in nature is anything static. It’s dynamic, whether subtly or significantly so. The seasons change. Temperatures go up and down. The length and intensity of daylight changes. Animals display differing activity and food consumption patterns. In polar regions these alterations are magnificent. But they are also modestly present even at the equator. So, if the natural world fluctuates throughout the year — and we humans are natural beasts — should we always eat and train in the exact same way?
That’s what I’m going to discuss today. The seasonality of lifestyle as it relates to not only peak performance, but health and longevity as well. We are indeed modern humans but if we take a look back for, say, 3 million years, our genome is built around a hunter-gatherer model which was integrally connected to the seasons. Things changed a bit in this regard 10-12,000 years ago with the advent of agriculture, but it’s really only been a few hundred years that we’ve been existing with a relative disregard for seasonal patterns. At least to some extent.
Those several million years of evolution crafted the biology of humans to be circadian-based. That change in daylight hours, intensity, and temperature triggers extremely specific adjustments in our hormonal balance and metabolic regulation. Even though we are modern humans, our inner beasts are ancestrally wired to flow with the alterations of the natural environment. Seasons drive hormones which facilitate functional states. Big time. Like it or not, we are designed to eat, move, and sleep in accordance with the seasons.
Sure, in the modern world we can alter our environment, and we have the power to cognitively override our ingrained, instinctive patterns. But doing so stresses the system unnaturally. The human, in good health, is a very durable beast. We can take, or get away with, some digressions. But practice unhealthy eating habits, activity, and sleep patterns, consistently and without letup for long enough, and the body breaks. Through many years of observation in clinical practice, I’ve come to call this phenomenon the “30-year rule.” In other words, If you throw insults at your metabolism long enough and hard enough (it seems to be about three decades give or take), things start to fail. The metabolism dysregulates, you gain weight, your blood pressure goes up, you become diabetic, your performance declines rapidly, your joints and tissues fall apart, and you ultimately get cancer or heart disease. But if you take even a few breaks from this abuse now and again, the durable beast rebounds and gains a little more time. You avoid quoting the late Warren Zevon and saying “My s**t’s f***ed up!”
I’d like to propose a model of seasonality that I use myself, as well as with my peak performance coaching clients and our online training community, the Training Tribe. I probably need to come up with a catchy name (and someday might) for this but for now I just call it Seasonality. I should probably distinguish this from the seasonal periodization model in athletics (which I also use in some instances) that involves partitioning the year around actual sports seasons rather than weather. This would be the classic off/pre/peak/post seasons of training and competition. It’s one way of designing programs and it is often mandated by the timeline or months of the year in which any given sport has its peak season. I realize I’ll take some heat for saying this, but some of those are unnatural and undesirable for the best health, and even performance of the human. If we can’t change the sport to match the seasons of the calendar, then we just find ways to make the best of it. But I think it’s always going to be suboptimal.
Here’s the “why” of that last paragraph. Forcing biology to exist outside of its norms is an overstress. You don’t try to plant a tree when the ground is frozen nor do you attempt to stand up a wall in a hurricane. Those are extreme examples and using an unseasonal lifestyle approach tends to be more subtle in its effects, but those impacts exist nonetheless.
Now that I’ve made my case, allow me to present a graphic (which is a work in progress) that represents my model of seasonality. It depicts how sleep, average intensity of training, overall volume of training, total caloric consumption, and carbohydrate intake might work best in the human organism. This model is a mix of scientific data and my own experience and opinion. I see this as a flexible concept but I fully believe in it and am willing to debate it with anyone.
I’d like to offer a few perspectives before we interpret the graphic. Intentionally, there is no scale on the graph. This is because the goal is to show general trends and relationships and not specific parameters. Yes, a low amount of sleep might be 7.5 hours and 9 might represent the higher end for one person, but perhaps not the next. Likewise, volume of training or calories is entirely individual and context-dependent. If you don’t mind my saying so, let’s try to see the big picture here and you can sweat the details on your own (or with a good coach). Also, I’d like to reinforce the interdependent nature of these 5 variables. As light drives hormones, so should there be a relationship between training and sleep, volume and calories, intensity and carbs, etc. I’ll describe each parameter separately, then offer up a quick summary.
Sleep is the foundation of our existence. Vitamin Zzz! There is solid evidence that indicates our drive to sleep, and to do so for longer time periods, is greatest in mid-winter around the time of the winter solstice. And conversely, we typically seek and require slightly less sleep in mid-summer. Much of this difference is attributed to how the levels of sunlight affect the balance of melatonin and cortisol within the body.
By intensity I mean the average intensity of training. You can and should perform high intensity training on a nearly year-round basis. You just shouldn’t do as much of it in December as you might in July. Obviously, humans don’t hibernate like bears, but we are wired to practice a bit more energy conservation in winter than summer.
The volume line on the graph refers to the overall volume of training, as well as general daily activity, you perform. In effect, this is how much time or distance or load you add up in any given time period such as a month. In my model, this typically peaks in or around September. If you use that ancestral lens, this time period potentially represented the highest amount of gathering, hunting, shelter building, migrating, etc. In fact travel, expanded social contacts, and community interaction should be highest in late summer and early fall.
Calories are pretty self-explanatory. What’s the total energy value that you consume at any point in the year? Historically, this was driven largely by food availability. Food sources were generally most abundant in late summer and early fall. Our appetite-regulating hormones, including ghrelin and leptin, affect our relative levels of hunger and satiety. Remember light drives hormones. The human body strives to feed aggressively during this time period. Much of that instinct may have been developed in order to stockpile calories as bodyfat for the lean times to come in winter. Today, we generally don’t have a problem with food availability, in that it is constant, but we’ve not yet evolved away from the pattern we’ve built over several million years. Additionally, the length and timing of our eating window should shift in seasonal fashion. In winter, we should ideally consume our meals over a shorter period of time, such as 8 hours, and that window should conclude by sunset (earlier in the evening). In summer, a longer and later-ending eating window is appropriate.
And lastly, how many grams of carbohydrates do you eat per day as you go through the year? Without even entering the debate over whether athletes should eat high carb, low carb, keto, or carnivore…let’s just consider carbs in the omnivorous human diet. Prior to agriculture, carbs were either only or mainly available in summer and fall. This was somewhat dependent on latitude but it is still true to a lesser degree even at the equator. Plants grow and ripen seasonally as per the dictum of nature, as opposed to doing so on a random basis. Because of this pattern, humans are actually more insulin sensitive in the warmer months because our organism evolved to optimize use of available carbohydrates at this time. Whether you prefer to eat a lot, a little, or no carbs, your body is programmed to do better with them in summer and fall. In winter there is a relative downregulation of glucose metabolism and an upregulation of fat burning ability in humans. Hard-training athletes do get a bit of a by here, in that the athletic body is better at glucose disposal than the genpopper, but some degree of prudence is warranted.
Ok, now that I’ve described the model and you are either amused, intrigued, or pissed — let’s look at some considerations regarding seasonality in training.
First of all, please recognize that this model is applicable worldwide, but as I have presented the graphic, it’s a northern hemisphere alignment. If you live in Santiago or Cape Town, you’ll need to invert the lines to align with your seasons, or switch the baseline to run from July to June. And, if you live very close to the equator, in all likelihood the slope of your lines may be less pronounced due to the more subtle alterations in light and weather.
You might be saying “But I live in Phoenix, and it’s really hot in summer and quite pleasant in winter. We tend to hunker down in July a bit and then get more active in January.” While that statement may be trueest in the sense of the modern human and activity patterns, light trumps temperature. In other words, that circadian-linked hormonal pattern will still exist, although more subtly. We need to consider the patterns of primitive people more so than modern humans who have manipulated their environment extensively. I’ve lived in the desert so I’m not talking out of the wrong orifice. You can get away with more volume of training in the winter, but ironically, you feel like doing it more in the summer.
“Beyond all this physiological and philosophical talk, what are the straight-up suggestions you make for most athletes?” I’m so glad you asked…here’s my short list. I’ll frame it up so we are looking at the current time on the calendar which is mid-December.
- Make an effort to sleep more (and always well) in winter. Your body will use this not only as a daily restoration cycle, but for seasonal health and longevity benefits as you regenerate for the coming year. All the usual sleep hygiene tips we are always talking about are perhaps most important in winter.
- Train more briefly than you do at any other time of year. We want consistent training and mixed intensities, but workout duration should be shorter than in other seasons. Embrace the microworkout.
- Train when the sky is light. This is a bit of a challenge when daylight is very short, but do what you can. A microworkout at lunchtime is better than a 90 minute grinder under artificial lighting at 5:00am or 8:00pm.
- Exercise with varying intensities, but perform most of your workouts at low intensity. Just touch on your high intensity work and don’t live there at this time of year.
- In fact, if you look at the last 3 points more closely, this is one of the reasons why New Year’s resolution “get in shape and lose weight sufferfests” almost always fail miserably. Trying to force a human to train at high volume, frequency, and intensity at this time of year is counterproductive. It fights genetic programming and goes against intrinsic biology, leading to increased risk of injury, breakdown, and burnout. Save the crusherfests for summer and if you are trying to lose weight, always remember that the fork is more powerful than either the dumbbell or the running shoe.
- Eat less calories than in summer. You’re sleeping more and training less, and you just don’t need as much fuel. Try some intermittent fasting and time-restricted feeding. Experiment with temporary caloric deficits. Reduce the number of meals and snacks you consume. Don’t starve yourself, just explore with an open mind.
- Reduce your carb intake to some degree. This is always a hot button with modern human athletes. Almost all of us love carbs and are addicted to them, including me. But carbs go best with high volumes of training, and particularly with high intensity. In winter, if we are following the aforementioned ancestral patterns, we’ll need less carbs than in summer, and reducing our intake facilitates the burning of bodyfat for fuel. If you are interested in “going keto” this is the time to do it. Our ancestors naturally used ketosis in winter as the preferred metabolic condition.
For other times of the year, you can simply draw a vertical line through the graph at any given month and extrapolate the relationships of the 5 variables.
“But what if I play a sport that isn’t aligned with this model? What if I play basketball or hockey and our peak season is mid-winter, often with games and practice times late at night under bright lights?” Well, you are not totally screwed here, but this does represent a challenging and slightly unnatural situation. But the human is a durable beast. When you are a recreational athlete or a dedicated fitness enthusiast, it’s easy to make changes in your patterns. But if you are a professional, collegiate, club, or high school athlete…you usually can’t change the way the program is set up. In this instance, you have to look at health and performance a bit separately. Yes, it is possible to be both optimally healthy and peak performing simultaneously, but it is less probable when your patterns are evolutionarily inconsistent. Therefore, experimenting with sleep, nutrition, training where it can be modified, and reducing other stressors in life to offset the stress of your sport (even though it’s fun…or your job), is critical. Literally all of the top performers across sport, especially those who have had long careers, have learned to embrace the tuning of every aspect of lifestyle to enable them to do their thang.
In closing, I’d like to emphasize a couple thoughts. First of all, any model regarding lifestyle is always going to be context-dependent and will need to have some flexibility built into it. You’ll have to study and experiment, and work with your coach, to get the best results. Second, if you can pull back from the modern hampster wheel of social-media, misinformation, and motivation applied incorrectly, you might be able to utilize these principles to your benefit. You just might enjoy maximum health and peak performance over a long lifespan. You’ll be a Lifetime Athlete!