Do you really need scheduled rest days?

Rest days are a curiosity to me. Why do we need a day when we’ve just been not exercising for the past 18-23 hrs? Exercise for 2 hrs, rest 22, exercise for 2 hrs, rest 22, exercise for 2 hrs, rest 46?…that’s all a rest day is, approximately, extending the period between exercise bouts to twice as long once in a while. Once to twice per week for most people. Do you need it?

As I’ve mentioned before, the human brain categorizes and compartmentalizes what we experience in order to simplify the world so that we can make sense of complexities and relations. The daytime-nightime cycle is intrinsic to our lives. It should not be surprising that we organize our behaviors around it. Our biology is organized around it. We call daily cycles circadian rhythms, or circa dia - around the day. In doing so, however, we often expunge salient features of time and biology that could otherwise shed light on important interactions to help our training. 

Let’s start with a question: How often do you work out? You might answer, every day; I never miss a day. It would sound strange to answer, every 22-24 hrs. It would be stranger still to answer, I never go more than 20 hours without a workout. But maybe this is the more useful framing of time within which to view our workouts. At the very least, it’s a useful addition to how we view the context of our training sessions.

If we view life as a continuous flow of time, rather than chunked into days, we’re afforded the opportunity to view exercise in the context of stimuli through time without daily resets but rather the more accurate waxing and waining of biological conditions.

Imagine the following schedule: you wake up, meditate, run, work [during which time you're in various states of mental and physical activity], return home or go to some event, watch television, and go to sleep. Along the way, you eat a few times and maybe do some other things. The next morning you wake up and do it all again. What if I had started my description at lunch or dinner - it would have sounded ever so slightly odd to you. We are wired to think of waking up as the daily start. And though there are measurable variables like cortisol that are high when we awake, there’s no more reason to draw a line in the sands of time at that point than an other. 

We can graph all of the measurable variables from our heart rate to hormone levels to mental attitudes and see sets of patterns that undulate over periods of seconds, minutes, hours, days, months, and maybe even years. Throughout the day, the cells of your body are acting and reacting within their respective environments and to the demands placed on them in the context of the factors depicted in that graph and all the other factors we might graph if we could measure them. When you’re stressing one cell, like a muscle cell during exercise or cleaning the house, it may be struggling to meet the demands you’ve placed on it. At another time, that cell may be resting - such as when you're sitting at your work desk - and it can now put more energy into recovering from the earlier stresses or even building improved capacities. At another time, you may be walking quickly across a parking lot or fighting a virus you just picked up and those physical and biochemical stresses may challenge the balance of functions within that same muscle cell. 

We now have a picture of the fluid mosaic of pressures and demands that any cell experiences over time and that these are unique but intimately intertwined with the experiences of all the cells and structures of the body through signaling and communication.

So, why do we take a rest day? Unless you schedule specific activities to do on your rest day (like grocery shopping), then the only difference between a rest day and an exercise day is that you aren’t running for about 5-7% of the time. The other 93-95% of your day is the same. There’s already a lot of rest, or at least opportunity for rest, every day. The rest day simply inserts some other activity, presumably less straining, into that 5-7% of time and extends your non-exercise time from about 22 hrs to about 46 hrs. Is that useful?

Let’s imagine another scenario. If your training program was to walk for 10 minutes each day, would you need a rest day? Surely not. What if you walked 20 minutes per day? What if you ran slowly 5 minutes per day? Would you need a rest day in those programs? Of course not. In fact, you’d detrain on such a program even if you never take a rest day because those workouts don’t even rise to the level of maintaining your current level of fitness. On the opposite extreme, imagine that you ran hard for the first 30 minutes of every waking hour of every day; you probably wouldn’t even make it one day - the next day, at least, would have to be a rest day. 

Now recognize that you’ve just been visualizing the workouts and leaving the entirety of the rest of each day as some out-of-focus, out-of-mind patches between the workouts. Your attention was totally on the workouts and you aren’t even seeing the vast majority of time - the time between workouts. That creates a great distortion in our view of our training, which should be broader and more open. In the words of the Nobel laureate Daniel Kahneman, what you see is all there is. Let’s increase the f-number on our lens and bring into focus the reality that we already do a lot of resting relative to the amount of time we exercise. What we do with that time, how we rest (what we eat, what we think, how we sleep), can now be seen in their rightful places high on the list of objectives.

There’s nothing magical about a rest day any more than a rest hour. Taking an additional 24 hours on top of the usual 22 or so hours of rest is like a hedge bet in the portfolio of training anchored in a circa-dian mindset. There’s nothing wrong with it as such, but it’s nothing more than an extended period of the relative rest you already get every day to hedge back from the uncertainty of possible over-reaching. Just like any hedge investment, however, it also mitigates gains.

There’s almost no research specifically testing the efficacy of rest days directly. But, one of the few examples is a 2014 study of half-ironman triathletes, which found that faster athletes took fewer rest days https://www.ncbi.nlm.nih.gov/pubmed/23707141. Of course, we can find a much larger body of literature pushing athletes to the breaking point with workout strain and relatively little recovery that documents all the debilitating outcomes of over-reaching and over-training. Perhaps a framing born of the availability heuristic, we then create a training scale that seems to only go in one direction and contrive a thing - a rest day - that we employ with regularity to avoid that overreaching while forgetting the 93-95% of the day that we’re already naturally doing it.

When the strain of your exercise and other life stresses outweight your recovery, you break down. When there's perfect balance, you’re be able to continue doing all the same workouts but you won’t get any better. If your body can be stimulated to become more than it currently is and you give it both the resources and relative rest to do so, then you'll adapt to become a stronger and faster runner. 

You can’t train hard every day. Hard efforts take more than 24 hrs to recovery. You can get away with stacking a few hard days together, but you do eventually need relative rest. That doesn’t necessarily mean a full day off, but it does mean more than 24hrs where you aren’t working so hard. Otherwise, you break down. What used to be easy will feel harder and your strong efforts will be slower.

If you want to be fit and healthy, it’s fine to go out and run 5 miles per day at an easy-to-moderate effort. If you’re unfit, you’ll get fit. Once you’re fit, you can stay fit by doing the same activities in more or less the same routines. But, if you want to become a better endurance runner, you have to continually push a bit beyond comfortable to improve. That requires larger stimuli so that there are additional adaptations, beyond simply optimizing health. Doing this requires hard training days - whether fast, long, or both. You can't tolerate doing that every every 6, 12, or 24 hrs for more than a few cycles. In order to run fast or for a long time, you have to be fresh enough to hit those paces or endure those distances. That requires a sufficient amount of relative rest.

Let’s say you have a hard running session every 72 hours, that’s every 3 days; maybe it’s a 2 hour workout. During the 70 hours of relative rest, what are you going to do? You should be sleeping well, eating well, and thinking well. Remember, it’s really all about how you sleep, eat, think, and move. You’ll also engage in all of those other things you do in life like work at your job, read, cook meals, do things with family and friends and so on. For the most part, all the cells involved in the hard workout will be able to work on repairing, recovering, responding to signals, and adapting. If you put the exercise stimuli too far apart - if you only run once a week, for example - you begin to detrain before the next run because those cells and tissues that recovered and adapted begin shifting back toward their default states. Inserting other challenges between workouts like hot yoga, staying up all night, catching an illness, or worrying about an upcoming deadline may slow recovery. Our goal is to continually nudge - stress a process a little bit, then back off enough for recovery and a bit of adaption, then repeat. But there are many functions that contribute to you becoming your ultra best. So, while some functions are recovering from being nudged, you can nudge other functions.

If you insert easy runs on the days between fast intervals, what happens? The overall stress is low on the easy run and the main physiological structures and functions that are used for the easy run are not the ones that were pushed to their limits in the prior fast interval workout. There is some overlap but we fail ourselves if we view our running as a stimulus on a single stress gauge, to be raised and lowered simply by the balance of general effort over time. It doesn’t work like that. Instead, there are myriad processes, structures, and pathways that are involved in accomplishing each run and that are unique to that run. Depending on the nature of the run (like speed, distance, and terrain) and your psycho-physical state, some of those processes, structures, and pathways are pushed to their limits while others are not. Each run is unique and each run stresses the body's processes, structures, and pathways to different extents.

Easy runs between harder runs ensure that you don’t lose endurance. Please do not call these recovery runs. They are not runs that stimulate recovery. They may be runs that you do while the net balance is in the recovery direction, but that does not make them recovery runs. Rather, a run at an easy effort is a stimulus for development. This is one reason we have to avoid calling hard days ‘workouts’. Even your easy runs are workouts. The runs that are often labelled as ‘recovery' are also workouts. Specifically, they are workouts to maintain or promote endurance. In fact, it takes a lot of running to develop and maintain endurance. Those easy runs you do between harder days are not recovery runs, they are endurance stimuli between strength, speed, or power stimuli. There may even be ways of using speed training to develop endurance. The key point is that while every run may require essentially the same organs, the characteristics and context of any individual run will determine which components are stressed more than others. And that means you can alternate stresses day-to-day such that something that was nudged to its limits in yesterday’s run is not getting much stress in today’s run and therefore is in a state of relative rest and recovery.

Do you need a full rest day? No, not necessarily. If you do, take it. But maybe you don’t. Certainly don’t fall into the trap of accepting it as dogma or using it as a hedge on your training without thinking it through in the context of a plan that suits you best.

As we get older, this question becomes even more important. Older individuals must maintain functional capacity and strength to avoid frailty. That’s best accomplished by maintaining some level of endurance and doing workouts with high intensity on a regular basis, especially heavy weight lifting. We become less sensitive to training stimuli, particularly for strength, as we age and it requires heavier weight lifting to maintain strength and functional capacity. For older individuals, it's useful to exercise every day if possible, such as alternating aerobic-style training with heavier weight lifting every other day. 

That may surprise many who think that older people need more recovery time. The perception that older people need more recovery time comes from the reality that most older people are less fit. People who are less fit, regardless of age, need more recovery time from the same workout. It’s true that there are genetic programs for growth that are on throughout childhood and adolescence, that these promote fast recovery, and that these slowly turn down or off into our 30s or even 40s but it’s equally true - and more important to appreciate - that older athletes recover much faster than their sedentary age-matched peers. The goal is to develop exercise tolerance slowly while aiming for the right amount of intensity that is sustainable on an every day workout schedule without injury because one day off due to injury quickly becomes 2 weeks off - exactly the opposite of what we’re trying to accomplish. You may not be 87 years of age and concerned with hip fractures right now, but you may be one day. So just tuck this bit of information away for when it’s needed.

Two core principles in my training philosophy are to keep variation in training load down to a comfortably adaptable level over time and to apply changes to training where they’ll have the most benefit for the smallest risk. That approach extends to the manner in which we increase training load as well. You can add volume to your training program by adding a few minutes to each run during the week or adding a second short run on any day. You’ll get more benefit from extending a one hour run to an hour and a half than you would by adding 30 minutes onto a run that’s already 2.5 hours long. Another great way to increase your weekly volume is to have an easy run on your rest day. Then keep good notes in your training diary and focus on maximizing your rest and recovery quality throughout the day by eating well, sleeping fully, and practicing awareness of your thoughts and emotions. You’ll get much more benefit and it’ll be more sustainable over years to have an easy run on what used to be a rest day than extending your long run even longer such that you then require that day off just to be recovered for the following week. My prediction is that the more rest days you truly need, the shorter your running career is going to be.

Too many people miss the opportunity to recover every day. They push themselves too hard for 5-6 days then expect 1 or 2 total rest days to unload the baggage and reverse the damage they’ve heaped on themselves. That’s like getting too little sleep every day of the work week and then expecting to make up for it by sleeping in on the weekend. We absolutely, positively know that doesn’t work. The question you want to ask yourself is, “Am I doing the best for myself right now?”. 

More than 90% of every day is recovery time from your exercise session, use it wisely. My thesis is not that there's anything wrong with a rest day. I simply want you to pay more attention to the 90% (or more) of your day that provides the same opportunities. And that if we don’t pay attention to living deliberately in that 90% of the day, then rest days will become necessary. If you absolutely need a rest day every week, then maybe it would be wise to evaluate whether your training or your lifestyle should be adjusted for the sake of your long term health and happiness.

Just as our and brain organizes life into 24 hr bins, we often plan our schedules in weeks. There’s nothing special about a seven-day period from a physiological standpoint. Your cat or dog do not know the difference between Tuesday and Saturday - except for the cues you provide them by leaving for work on one of those days or behaving differently because of different attitudes on those days. So, yes, we do have measurable differences and rhythms in our physiology across a week but those are created by our lives revolving around the mental construct of a week rather than any necessary physiological rhythm. It’s possible that a weekly rest day fits that pattern in modern society. But also appreciate that it’s just as reasonable to simply take a rest day when you feel you need it, independent of the neat organization of a calendar.

The most important point I can make is that you should rest when you need it. If you don’t need it, then you don’t need it. If you do need it, take it. If you need it every week, then maybe use the time in your next rest day to evaluate if your program is too aggressive or if you can improve your recovery quality by making better eating, sleeping, or thinking habits. Runners who survive the tests of time and continue running well for many years are not the ones who never miss a workout or who necessarily stick to a rigid schedule (workouts or rest days). Rather, they're the ones who are consistent about steadily and manageably nudging their bodies while listening to its feedback and paying attention to all the facets that contribute to their overall health. I’ll rest when I’m retired, I’ll sleep on the weekend, I’ll recover on my rest day are all red-flag statements.

Science Of Ultra is more than just a resource on how to exercise to be a better endurance runner, it’s a source of knowledge on how to live an ultra life. I want you to become your ultra best. It’s about the science of ultra living, it’s the soul of being your best - see what I did there…SOUL, science of ultra living? It’s my mission to bring you valid, reliable, and actionable information to help you eat well, sleep well, think well and move well. Because those are all equally important to feed your SOUL with the nourishing SOUP that fuels your journey to becoming your ultra best.