I was talking to someone yesterday regarding some changes in his biochemistry that suggest his adrenal glands are not functioning as well as they might. This is important, because the adrenal glands (which sit on top of the kidneys) have a multitude of roles, including the secretion of hormones in response to stress. For many years this man had been a useful runner, and clocked up significant mileage at a decent pace each week. Because this is quite hard work on the body and the adrenal glands, I suggested he, among other things, pulled back a bit on the running. I suggested that he might think about substituting it for a less intense activity like brisk walking.

I also used to run a lot, and as a result of this and other old sporting endeavours (rugby, mainly) ended up with quite few joint-related issues including pain in my ankles, knees and sacroiliac joints (a joint in the back of the pelvis). Repeated cycles of running/injury/rest/running and ever-frequent visits to the osteopath convinced me that I needed to find another principle form of exercise. I chose walking, though it took me two years getting over the ‘shock’ of kissing goodbye to running before it occurred to me that walking might be a worthwhile and viable substitute.

For people used to running, walking can appear to be an exercise that just doesn’t cut it. But actually there is quite a lot of evidence (some of it detailed elsewhere on this site) that walking can have significant benefits for health. It is much easier on the body than running, and because of this is much more appropriate, I think, as we age.

One of the things I asked the gentleman I was talking to yesterday to consider was this: Can he see himself running in his 80s (assuming he makes it this far?). The reality is that while running in one’s 80s is possible, it is not, maybe, likely. That means that some time between now and then, this man is going to need to find a viable alternative to running if he wants to retain relatively high levels of activity and the benefits that come with this.

And on this subject of benefits, I was interested to read a recently-published study which looked at how much walking appears to be required for significant benefits for health in older adults [1]. In this study, Japanese researchers assessed physical activity using two devices: a pedometer to measure numbers of steps and an accelerometer to measure speed. Several hundred men and women aged 65 or over were assessed for 24 hours a day for more than 8 years.

The researchers involved in this study then looked at what levels of activity appeared to be associated with benefits for physical and mental health. What they found was that improved physical health was seen in individuals taking 8000 steps at an intensity of more than 3 ‘METs’. MET stands for Metabolic Equivalent of Task. One MET is the energy expended at rest. So if someone is engaged in an exercise that burns 3 times as many calories as are burned at rest, that exercise is 3 or more METs in intensity. 3 METs equates to walking at a speed of 5 km/hr (about 3 miles an hour or a mile completed in about 19 minutes).

The threshold above which there was an associated with benefits for mental health was lower: only 4000 steps a day at 3 or more METs.

The main issue with a study of this nature is that it is epidemiological in nature, and therefore only tells us that there are associations between physical activity and benefits of health. It does not assure that the physical activity caused the better health. It could be, after all, that individuals who are in better health are more likely to be active.

However, physical activity can induce changes in the body that we would expect to reduce the risk of chronic disease and enhance. All-in-all, the evidence suggests that walking has considerable potential in terms of improving and maintaining health, and this may be particularly important as we age when walking may end up being one of the forms of exercise we have the capacity to engage in with relative ease.

References: 1. Aoyagi Y, et al. Steps per day: the road to senior health? Sports Med. 2009;39(6):423-38.