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How important is physical fitness for longevity?

The Copenhagen study of middle-aged men put figures to the expected years of life gained at different levels of fitness. More than 5,000 men aged around 50 had formal exercise testing. They were then followed up for 46 years. Compared with those in the bottom 5 per cent for cardio-respiratory fitness, those with low normal fitness lived an extra 2.1 years, those with high normal fitness lived an extra 2.9 years and  the top 5 per cent lived an extra 4.9 years.

As with taking up exercise later in life, older individuals who improve their fitness also improve their life expectancy. In a large epidemiological study involving older male veterans (65–92 years) with on average an eight-year follow-up, the lower the exercise capacity, the greater the risk of death. Mortality risk was 12 per cent lower for every 1-MET increase in exercise capacity, regardless of age – remarkably similar to the finding above. The biggest relative benefit was found for the higher fitness groups.

How does physical fitness compare with other indicators?

The risk of you developing heart or cardiovascular disease (CVD) is assessed by using all your risk factors to create an estimate of the chance of developing CVD. The usual instrument used is the QRisk 3. Some of the risk factors which QRisk 3 takes into account are age, gender, family history, ethnicity, post code, smoking history, body mass index, blood pressure, blood lipids, and the presence of a number of conditions such as diabetes, atrial fibrillation and kidney disease. The result is expressed as a percentage chance of developing CVD over the next ten years. Above 15% is reckoned as a level which might need intervention such as the prescription of a statin. Mind you, if you are male and over 70 you are almost certain to have a risk of more than 15% over the next ten years.

But what’s missing from the risk factors? Yes, you guessed it – no mention of exercise habit or physical fitness.

There are plenty of studies which show that that taking more exercise (assessed by the individual) lengthens life. Now we have much more convincing evidence about the effect of increased physical fitness – cardio-respiratory fitness (CRF). Investigators examined the deaths in 750,000 US Veterans aged 30 to 95 years who had had their CRF measured by treadmill testing. The follow-up period averaged 10 years during which time 175,000  had died. There was a striking correlation between decreased CRF and mortality. The risk was four times greater for the unfit compared with the fit. Moreover the CRF level was a better predictor of mortality than any other risk factor including blood pressure, BMI, smoking and family history. Also there was no evidence that, as has been suggested by previous studies, you can take too much exercise .

And which exercise is best?

Whatever exercise you decide on is good – and it is my belief that defining which exercise is best is equivalent to moving the deck chairs about. The most important characteristics of effective exercise are frequency, intensity and duration of exercise sessions. This may explain the findings of another recent study which looked at the exercise habit of 272,000 US citizens. For cardiovascular disease the study found that compared to non-exercisers those who played tennis, squash or racquetball were 25% less likely to die.  Walking was associated with a 11% reduction and playing golf with a 9% reduction in risk. For risk of cancer death the reductions were 19% for running or jogging and 6% for cycling.

Are doctors or their paymasters listening?

Quick answer – NO!

When you visit a GP you will have such factors as pulse rate, blood pressure, weight, blood cholesterol etc routinely measured – but when were you last asked how much exercise you take? And has your CRF ever been assessed? These very important indicators of risk are ignored by QRisk 3. They are also largely ignored when it comes to the management of risk. If you warrant treatment of your increased risk of CVD you will probably be prescribed aspirin, a statin and a pill or three to lower your blood pressure. You might be advised to take more exercise but how often is that either defined or prescribed?

One contributor to this problem is the fact that a large proportion of GP income depends upon the Quality and Outcomes Framework (QOF). This system incentives GPs to meet a number of targets, each worth a certain number of points.  There are 78 different items for which points are awarded to a total of 401 points. Items include such things as keeping a register of certain diseases, checking on additional risk factors, achieving a variety of targets, measuring blood pressure, body mass index etc and prescribing certain drugs for particular conditions.

I can find only two items which relate of exercise or physical fitness:

  1. HF007 which is about heart failure and asks among other things “The percentage of patients with a diagnosis of heart failure on the register, who have had a review ……., including an assessment of functional capacity ……..”  (7 points).
  2. COPD10 asks “The percentage of patients with COPD [receiving] ………. an offer of referral to a pulmonary rehabilitation programme”. (2 points)

If you think that your GP is paying more attention to the computer screen than to you it is because his or her income depends upon it! Exercise and physical fitness deserve a place in QOF.

Summary

The facts are clear. Low levels of exercise and low physical fitness are both predictors of premature mortality and shortening of total lifespan. Low fitness levels have been calculated to account for 16 per cent of premature deaths, substantially more than any other risk factor, including cigarette smoking, diabetes, obesity, raised blood cholesterol and hypertension. And we should not be surprised that other measures of physical performance are also associated with longer life, including grip-strength, balance and also leg-muscle strength.

Increased lifespan is important, increased healthspan is even more important. Taking more exercise and getting fitter will achieve both.