Furthermore, walking can provide the kind of preventative benefits usually seen with the more vigorous forms of exercise. It can help stave off degenerative diseases. The Nurses' Health Study of 70,000 middle-aged women found that the risk of type
2 diabetes was the same for walking vs vigorous activity like running, providing that the energy expenditure in doing the activity was equivalent. Even among those whose daily activity levels weren't vigorous, the risk of diabetes fell, so long as they walked on a regular basis. The risk was lowest among the most brisk walkers (JAMA, 1999; 282: 1433-9).
In the US Women's Health Initia-tive Observational Study, involving more than 73,000 postmenopausal women, walking was just as good as vigorous exercise for preventing cardiovascular events (N Engl J Med, 2002; 5: 347: 716-25).
Although most people believe that running expends more energy than walking, in fact, 'power' walking at a pace of at least 5 mph (a 12-minute mile) burns more calories than running at a similar speed (J Sports Med Phys Fitness, 2000; 40: 297-302).
Walking also appears to promote identical oxygen consumption to running. When sedentary men began a six-month programme of endurance training, those asked to jog six times a week for 30 minutes consumed the same volume of oxygen as walkers walking for the same length of time and frequency. The only difference was that the joggers had higher levels of high-density lipoprotein (HDL; the 'good' sort) cholesterol. Nevertheless, another study of previously sedentary women (mean age: 47 years) found that brisk walking decreased heart rate and skin folds (an indicator of fat), and increased HDL cholesterol (Br J Sports Med, 1994; 28: 261-6).
Furthermore, it appears that just three months of brisk walking can lower levels of blood insulin (Metab-olism, 1995; 44: 390-7), and even a single fast walk will improve blood cholesterol levels (Metabolism, 1994; 43: 836-41). Brisk walking can also reduce bone loss in postmenopausal women (Clin Sci, [Lond], 1997; 92: 75-80).
Interestingly, exercise intensity also doesn't seem to matter in fat-processing. In a study by UK's Loughborough University comparing low- and moderate-intensity walking, fat levels in the blood and fat oxidation were similar among men with normal cholesterol levels (Med Sci Sports Exerc, 1996; 28: 1235-42).
The best news of all is that walking doesn't have to be done all at one time. Whether in one session or accumulated throughout the day,just 30 minutes of brisk walking can reduce blood fats and increase fat-burning (Int J Obes Relat Metab Disord, 2000; 24: 1303-9). In women, short bouts of brisk walking resulted in similar improvements in fitness and decreased body fat as did long bouts, so long as they were of the same total duration (Med Sci Sports Exerc, 1998; 30: 152-7). Indeed, three 10-minute bouts were also as effective as one contin-uous, 30-minute bout in reducing stress, tension and anxiety (Med Sci Sports Exerc, 2002; 34: 1468-74).
Nevertheless, you should probably go for a brisk walk at least five times a week to benefit. A bare minimum of 20 minutes three times a week is not enough to lower your risk of cardiovascular disease (Prev Med, 2005; 41: 92-7), but three 10-minute bouts a day can reduce cardiovascular risk and improve mood (Med Sci Sports Exerc, 2002; 34: 1468-74).
So, simply taking the decision to walk more during your day-whether to and from work, to catch the train or get to school, or even with the dog-can pay big dividends in terms of preventative medicine.
Walking is better than running
Running is undoubtedly hard on your lower limbs. A year-long Australian study found that distance-running injuries were the second most common sports injury seen at a sports clinic. (Clin J Sport Med, 1997; 7: 28-31). Runners commonly suffer from overuse injuries of the lower limbs, including stress fractures, and soft-tissue injuries such as shin splints, Achilles tendonitis, knee pain and other problems, ranging from simple inflammation to structural degeneration (Scand J Med Sci Sports, 1996; 6: 222-7).
The best preventative for such injury is to slow down, cut down the duration, add stretching and/or warm-ups and cool-downs to your routine, and change or improve your running shoes (Cochrane Database Syst Rev, 2001, 3: CD001256).
But even walkers have to walk with care, so here are a few useful tips:
- Walk with your abdominal muscles tightened, and roll back your shoulders, lift your chest, keep your head up and your arms in a rhythmic swing
- Push off from the toes and land squarely on your heels with each step, then roll from heel to toe
- Make each stride a comfortable length
- Wear good-quality, well-fitting walking shoes and replace them regularly.