Photo credit: Run by Flickr user Satish Krishnamurthy, used under a Creative Commons Attribution 2.0 license. Image is included in the Predawn Runner / Running Manifesto Calendar and is also available as a Predawn Runner Mouse Pad.
A recent post in the Well Blog of the New York Times provides another reason to become a Predawn Runner (as if the 20+ reasons provided previously for running predawn weren’t enough). It appears, based on a study out of Belgium, that exercising before breakfast provides greater health benefits than exercising at other times of day. The benefits specifically focus around maintaining weight in the face of a deteriorating holiday diet – one can presumably extend this conclusion to cover losing weight or maintaining weight with a more reasonable diet as well. This is great news for those of you already committed to exercising early – but note that there are certainly a lot of caveats regarding this study, as there typically are for any such “research” leading to such sweeping conclusions.
First, the benefits cited are really related to exercising in a fasted state, not specifically to running predawn. Obviously, for most of us, the only realistic time to exercise in a fasted state is before breakfast, so this is a minor caveat, but for precision sake it is best to make sure the cause-benefit relationship are more directly understood.
Second, the study focuses specifically on young men, and, as implied by the statement that the control group had to be convinced not to exercise, one can assume they were already in respectable condition with reasonable health habits. This, again, may not be much of a caveat, but it would be fair to question if the same results would be achieved (at least as dramatically) with women, or with older men. Perhaps metabolic patterns are different, and this may drive different results – though there is other evidence that exercising in a fasted state yields more fat-burning benefits, and the logic as to why this occurs is sound.
Third, the subjects seemed to participate in intense workouts for a 60-90 minute period. Thus, it is unclear if performing a less strenuous workout or doing so over a shorter period (say, 30 minutes) would result in the same difference in fat-burning results. Thus, a three- to five-mile recovery run may be just as valuable at other times of the days (though you can refer to the other 20+ reasons as to why you may want to get it done early).
Finally, the benefits sought were strictly around weight loss or maintenance. As the post notes, this doesn’t necessarily bring benefits to your performance during the workout or to your conditioning or preparations for a future goal (say, meeting a 3:00 marathon). In fact, other studies have claimed that performance tends to be slightly better in the afternoon, for various (and perhaps not fully understood) reasons. However, the same post points out studies that indicate the body adapts to the time of day you “normally” choose to exercise. Of bigger concern is the fact that relying on fat to generate your energy is less-efficient than having carbohydrate stores to quickly draw from – this can be more limiting on a longer workout, for certain and may be reason to take in some calories in the morning before or during key long runs or even high-intensity workouts (admittedly, I rarely do this, and I can’t claim that performance has suffered because of it).
So, even if your intent is not strictly weight loss, it is likely that at least part of the benefit you seek from running is better overall health. If you’re not already a predawn runner, maybe it’s time to consider making the jump and getting a quick start to meeting your New Year’s resolution to live a healthy lifestyle.
Hat tip to Nathan Adkins for sending this article along to me.