16/11/2010 20:17:54
gymnag_Rob
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Posts: 105
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I recently entered a 50 mile ultra marathon, part of which involved grouping runners for the part of the race that was during the hours of darkness. One of the people I was grouped with was a 64 yr male runner who was a veteran of quite a few ultras. Not only did he complete the race but he came in the top twenty (out of an entry list of 550) beating many runners less than half his age!
Intrigued by this I asked him his personal views, from his own experience, on staying fit, injury free and healthy into your sixties, whilst still completing massive mileages AND still being competitive against runners of all ages. He was kind enough to send me some interesting material that explains what in his opinion is the key to keeping fit and healthy into old age, the processes by which we age, how much decline is inevitable and how much of this decline can be postponed if the right sort of action is taken as well as links to various research that has backed up these theories. This is not just useful for sports people but for anyone who wants to enjoy a fit and active old age.
The first subject he covered was VO2 max. This is the body’s ability to deliver and utilize oxygen. This has apparently been shown to decline by about 1% per year in sedentary people once the age of thirty has been met. However by exercising regularly this decline can be halved. The current theory is that the heart is to blame for this decline as the max. heart rate drops by about 1 beat per minute per year. This leads to the conventional belief that less oxygen is therefore delivered to the muscles during hard workouts.
However research (by Darren McGuire and Benjamin Levine from the University of Texas Southwestern Medical center and Presbyterian Hospital in Dallas*) suggests that as people age, VO2 max declines not because the heart becomes less able to deliver oxygen but the muscles become less able to use it. It was found that the volume of blood pumped with each heartbeat increases with age, as the heart becomes larger to force blood through arteries stiffened with age and this increase in volume is enough to offset the decline in maximum heart rate. This would indicate then that the drop in VO2 max as we age is not because of the hearts ability to deliver oxygen falling but rather a decline in the muscles ability to use or call on this oxygen.
As yet it is not known why this happens but perhaps arteries supplying oxygen to the muscles clog up, or signals from the muscles for oxygen are disrupted or there are less mitochondria to supply the oxygen. Regardless of the reasons, regular aerobic training can significantly improve your VO2 max. When McGuire and Levine put 50 year old men- who had previously been tested as healthy twenty year olds following three weeks of bed rest- on exercise programs that went up from 3 to 5 hours a week, their average aerobic fitness improved so much so, that their fitness was the same after six months as it had been when they were twenty.
It was found that three weeks of inactivity from the bed rest had caused a greater decline in fitness than thirty years of ageing.
(An interesting side note to this research was that one of the men involved in the research, who chose to cycle for his exercise, showed no improvement in his V02 max. However the VO2 max was tested on a treadmill not a bike and this would indicate that it is also the muscles, not just the pumping ability of the heart, that effects VO2 max. Perhaps as you need to develop the specific mitochondria in the muscles used, in order for the oxygen to be delivered and running and cycling have an emphasis on different muscles. It would therefore be useful to vary your training to maintain whole body fitness and also when training for a sport a good proportion of the training needs to be as specific to that sport as possible.)
Another factor in maintaining fitness into your latter years is too include high intensity training and strength training. By including a series of hard intense intervals into your training you can fire up your VO2 max up another notch and increase your fitness. However the more active your youth the less improvement there will be. Research also suggests that unlike your aerobic capacity your muscles cannot recover from years of neglect and inactivity. As we age we lose fast twitch muscle fibres more quickly than slow twitch muscle fibres.
It is a case of using it or losing it.
If people as they get older, stop doing high intensity activities, that recruit their fast twitch muscle fibres, the unused fibres atrophy and will eventually die. Slow twitch muscle fibres decline far slower as they are used for daily activities. It is therefore important to incorporate strength exercises, to prevent this decline and weight training is ideal for this. Apparently older people who start weight training late in life, will not replace their fast twitch fibres, they will only increase slow twitch muscle fibre, gaining strength and mass but without the power that comes from fast twitch fibres. Lastly as the body ages injuries take longer to heal and the key is increase recovery times and rest properly between intense or hard workouts.
To sum up then the key points to follow would be as follows;
1, Do some aerobic training.
2, Do some hard interval training.
3. Do some strength training with enough weight to activate your fast twitch muscle fibres.
4, Rest properly.
In light of the above, the minimum weekly exercise for people wishing to maintain fitness and health throughout their life would be something similar to;
Aerobic session three times a week including some intervals.
Strength training twice/three times a week.
A sprint session once/twice a week or circuit type class.
(or any other variations.)
* McGuire DK, Levine BD, Williamson JW et al. A 30-year follow-up of the Dallas Bedrest and Training Study: I. Effect of age on the cardiovascular response to exercise. Circulation 2001;104:1350-7
McGuire DK, Levine BD, Williamson JW et al. A 30-year follow-up of the Dallas Bedrest and Training Study: II. Effect of age on cardiovascular adaptation to exercise training. Circulation 2001;104:1358-66
edited by gymnag_Rob on 16/11/2010
edited by gymnag_Rob on 16/11/2010
edited by gymnag_Rob on 17/11/2010
edited by gymnag_Rob on 17/11/2010
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