TRAINING
Orienteering – a prescription for health
And other studies are beginning to reveal the metabolic and physiological bases of these benefits. Some of these benefits are associated with the acute effects of each bout of exercise, whilst other benefits are accrued through repeating these bouts on a regular basis (chronic benefits).
Steve Bird
In general terms, for our bodies to remain in good health, numerous factors need to be maintained within specific and permissible ranges, thus maintaining homeostasis. Examples of this include the concentrations of glucose and fats within our blood. If these become too high or fall too low, it will lead to illhealth and, in extreme cases, death. However, whilst we need to regulate these factors in our blood, our supply and use of them is not consistent. For example there will be surges in supply when we eat a meal and then periods of fasting between times. So to prevent their levels becoming too high after eating, our bodies have complex regulatory systems that are designed to rapidly store away the excess for later use. This storage also provides an internal source that can be mobilised when our blood levels drop in the hours between meals or when we increase demand for them, as when exercising.
Inactivity is recognised as a major health risk in Australia, and studies have suggested that approximately 20% of the health burden could be reduced if people exercised at the advocated levels. Nationally1, it is estimated that physical activity could prevent: – 33% CHD (coronary heart disease) – 25% Diabetes – 12% breast cancer – 15% stroke – 10 to 16% hip fractures In addition to these there is a growing body of evidence to support the efficacy of exercise in reducing the risk of other diseases, including colorectal cancer. So with all this evidence, does a regular dose of Orienteering represent your best buy for health? Well, although there have been relatively few studies, looking at Orienteering in particular, one study2 on male Masters orienteers in Finland showed that their risk of a heart attack was less than one-seventh that of inactive age-matched controls. Of course it could be argued that orienteers are a self-selected group, who may be less prone to heart attacks due to an innately better level of health. So to consider this further we must expand our discussion to consider walking and running activities in general, for which there is a large body of epidemiological evidence.
A weighty argument Many people are concerned about their weight, and according to national statistics, nearly half of Australian adults are either overweight or obese. However, despite all the marketing and expensive products being sold to help people reduce their weight, in most cases it is simply a matter of calories in (food) vs calories used (metabolism and exercise), virtually everything else is of minor impact. So to reduce weight, or more specifically, to reduce our fat stores, we need to use up more calories than we take in. And one of the ways to increase the use of calories is through exercise. Whilst the exact calorific cost of a bout of exercise will depend upon the individual; an hour’s vigorous exercise, such as Orienteering, will utilise around 600 - 900 Calories (kcal), depending upon how fast you’re running and how hilly the terrain is, etc. This is the calorific equivalent of about 0.08 – 0.12 kg fat. So if you do around 20 events a year, it equates to about 1.5 – 2.5 kg of fat (values estimated from Robergs and Roberts, Exercise Physiology, Pub. McGraw-Hill). Not a bad way to keep the fat off. But even if you’re losing this battle, don’t despair, because in terms of health, fat isn’t the whole story. For example, very large epidemiological studies have shown that whilst being fit and not overweight is the best combination for health, if you are active and relatively fit despite being overweight, your risk of heart disease is the same as someone who is not overweight but inactive (Lee et al3). And of course, being inactive and overweight is the worst combination. So the message is that being active is good for your health even if you are overweight. And, as indicated above, it may help you to lose those excess kgs, or at least stop you from putting on any more.
It’s in the blood Epidemiological studies have conclusively demonstrated that regular exercise reduces the risk of many chronic diseases. 16 THE AUSTRALIAN ORIENTEER JUNE 2007
However, some of our most prevalent chronic diseases such as heart disease and diabetes are associated with a failure of these homeostatic responses to work as effectively as they should. And consequently glucose and lipid levels are inclined to rise too high after a meal. This can even be seen in some people who have not yet succumbed to the full-blown disease, but are in a pre-disease state; and probably don’t know it. Fortunately exercise has been shown to restore much of this sensitivity. For example, it has been shown that for about 72 hours after a bout of exercise (the length of time does vary depending upon the individual, their age and the exercise), our systems for controlling blood glucose and blood lipid levels after a meal are more sensitive4. This means that they respond more effectively to the ingested food and prevent the levels of glucose and lipids from rising too high, and reaching the disease associated levels. Unfortunately these benefits wear off after a few days, and therefore in order to restore the benefits, you need to exercise again. Hence, exercise needs to be undertaken regularly to gain the full health benefit. Regular exercise also has chronic health benefits, such as producing a healthier blood lipid profile throughout the day (not just after a meal), with lower levels of the atherogenic Low Density Lipoprotein Cholesterol (LDL-C) and a better ratio of LDL-C with the cardio-protective High Density Lipoprotein Cholesterol (HDL-C).
Mental health When espousing the health benefits of Orienteering, it is important not to focus solely upon the physiological, and to forget the mental and social aspects. It’s a great sport, with a friendly clientele, and at the end of a hard challenging event, I’m sure many of us feel so much better for having focused on the challenges of our course, whilst forgetting the stresses of other aspects of our lives. And even on the occasions when we didn’t perform at our best, we can probably still coin the phrase that “A bad day’s Orienteering is still better than a good day at work”.
The complete prescription In truth, whilst Orienteering is certainly good for our cardiovascular fitness and health, it probably doesn’t cater for all our health needs. And some muscular strengthening work is needed, particularly as we get older. Interestingly, there is a growing body of evidence for the benefit of strength training in improving our glucose control, insulin sensitivity, and reducing the risk of developing diabetes. Also we must not forget the other factors that contribute to our health, such as healthy eating, not smoking, and not abusing alcohol.
