managing
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- Jun 19, 2014
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This conversation really highlights the question of "where is the stress line?" Jogging 5k doesn't seem especially stressful to me (with lots of caveats about who is doing it of course). I am not advocating doing it. Riding 5k? or 15-20 miles? With snack (fruit juice for example)? Sure. That is something I do and enjoy. Which doesn't mean it can't be stressful.Sorry, I believe you to be wrong on nearly all counts here. For a person in "excellent" health to be able to jog 5k without walking would implicate an adapted metabolism. As Peat explains, runners and joggers will have an adapted metabolism, slowing their thyroid function and heartrate down considerably, to lower caloric expenditure as much as possible. The result is a plethora of bad physiological effects, from hormones to bone structure. Most marathon runners suffer severe shin splints or osteoporosis or arthritis by time they are middle aged. Very few marathoners make it past 80, with most suffering from heart disease and various other health complications.
Running/jogging or endurance/aerobic training/excercise (whatever unloaded term you are comfortable with) is actually deadly long term, with the effect biochemically similar to being overweight. The body lowers the metabolism to compensate, compromising structure. Muscles are wasted first, and fat is more easily stored. Stress hormones, particularly cortisol (signals fat storage) are significantly elevated during runs and for long periods of time after. The effect is so prominent that I would never jog or run for longer than a couple minute at a time.
Weight training can also be stressful, but done correctly and given adequate time for recovery it can be very rehabilitative and help to permanently increase baseline metabolism and lower stress hormones. The important factor is not to give into the angst to workout too frequently, and for 95% of the population that is no more than once every 7 days assuming a workout was sufficiently intense. The returns begin to diminish once you lift weights more than once a week, because the stress hormones and lactic acid will begin to aggrandize. Running is a much more potent method of increasing lactic acid and stress hormones, though.
Having more muscle mass is also key to keeping off fat. 5 more pounds of muscle can burn an extra 200 calories per day, and that is when at rest. In contrast Running a few miles will burn only around 300 calories for the average runner, (less depending on how experienced you are). The average person will burn 100-150 calories just sitting still, so the net burn is not better than having a few extra pounds of muscle. Now add in the fact that endurance training wastes muscle mass (via increased cortisol etc) and its not unlikely you will lose 10-20 lbs of musclemass after sticking with a running routine for a few months. The calorie math says you are working much harder and burning far fewer calories, no better than when you were sedentary. The nail in the coffin is the studies that demonstrate most people will overeat after going on a run, and will overeat proportional to the perceived work they put into a jog. Thus, a person who ran a few miles to burn a NET couple hundred calories will reward themselves with a sandwich that may have 500+ calories, most of which will be stored as fat thanks to the stress hormones. This is EXACTLY why people, no matter how much they attempt to burn off those excess calories via treadmilling or playing pick-up basketball, etc, complain about gaining weight that is impossible to get rid of when they are in their 30's and 40's. When you are under 25 your metabolism is still strong enough to mitigate the damage and stave off the fat, but years of well-intentioned endurance training and unsaturated fats will damage the metabolism so much by time the average person is 45, they will find it next to impossible to not be overweight unless they drive themselves nutty eating <1000 calories per day.
I don't feel like doing long synthesis on the subject now, but the scientific data is abundantly clear. People eschew the empirical data, however, because running makes them feel good, if only for the fleeting period during and shortly after a run (endorphins/adrenaline). The stress has very negative long term effects, which are observable in the scientific literature. I read "Body By Science" which dissects this widespread misconception in detail, and is chalk full of sources.
So, I for one don't care which of you are right. I am leaning toward @sunraiser , but I'm not married to that notion. I'd much rather get it right than be on the winning team in this debate. So I'd love to hear more. Specifically, how can each of us determine what is too stressful for each of us? This probably needs to include (as you've done) some comment on what an appropriate recovery period is. The 20 mile rides are usually no more than once a week for me. Although I've been known to do 2 during ideal weather, optimal personal conditions.