It has long been emphasised through the media and by health professionals to focus on weight loss to improve health and decrease the risk of chronic disease and death. The most common/easiest way we can assess ‘healthy weight’ is through a BMI reading. Recent data however has made us question how important is it focusing on weight loss alone for health compared to increasing activity and cardio fitness?
The evidence for Physical Activity:
A recent study looked at how much of a reduction in death would result from just improving your activity compared with improving BMI and waist circumference. The biggest finding was that being physically inactive (no planned exercise during the week) resulted in almost twice as many deaths compared to having an unhealthy BMI (>30)! The greatest reduction in mortality rate was seen in people going from inactive to moderately active, a 20-30% decrease in people regardless of their BMI or waist circumference. This is also promising to see that even the smallest increase in activity (15-20 mins a day) can reduce risk of death.
The evidence for Fitness:
Physical activity is classified as any form of movement, be it planned or incidental. Fitness, on the other hand, is a specific score of cardiorespiratory health. Fitness levels can be measured through a proper test with your trainer or EP, or just looking at how you can improve your walking or run time gradually.
Research into your fitness levels is showing its similar significance to other health markers (such as BP, blood sugar levels and waist circumference). In another study, a 1-MET increase in cardio respiratory fitness resulted in a 13% reduction in all cause death and 15% reduction in CVD events. A 1-MET increase would be equivalent to a 1km/hr faster jog. This 1- MET improvement in health was comparable to a:
7cm waist reduction
5mmHg systolic blood pressure reduction
1mmol/L triglyceride reduction
1mmol/L fasting glucose reduction
This reduction in mortality and CVD through fitness was significant regardless of age, sex, smoking status or abnormal ECGS. It seems that we can reduce our risk of mortality through increasing fitness levels, regardless of total body fat and weight readings.
In a study of healthy, non-diabetic patients with similar BMIs, it was those with poorer fitness levels who had higher triglycerides, and total-Chol:HDL ratios. Fit men also had lower visceral fat, again compared to unfit men of a similar BMI suggesting that the protective effect of higher fitness is through lower abdominal fat.
Take home points:
Weight loss shouldn’t be the only focus/goal when it comes to a new exercise program. Ensure to look your overall physical activity and fitness levels too for improving health as the research shows it is just as important as weight loss alone
Always remember the benefits of regular resistance training, mainly to lower blood sugar levels and joint strength, as well as increasing fitness capacity (a fit obese person is comparable to a normal weight unfit person)
If your new to exercising, look at ways to increase overall activity in small ways first during the day (using a step counter or mobile apps)
Ekelund et al 2015. Physical activity and all-cause mortality across levels of overall and abdominal adiposity in European men and women: the European Prospective Investigation into Cancer and Nutrition Study (EPIC). American Journal Clinical Nutrition. Mar; 101(3):613-21
Lee et al 2010. Mortality trends in the general population: the importance of cardiorespiratory fitness. Journal of Psychopharmacology 24(11) Supp 4, 27-35