Personal Training and Cardio?

One day I was running on a treadmill at the gym, listening to Britney Spears blast through the iPod headphones of the woman walking on the treadmill next to me. A few minutes later, having suddenly noticed the absence of Britney's voice, I spotted the woman in the corner of the gym, her personal trainer watching her form as she performed biceps curls with dumbbells. Looking around the room, I saw a number of personal trainers supervising their clients as they squatted, lunged, bench-pressed, leg-curled and abdominal-crunched their way through strength-training workouts. It's the tradition among personal trainers to spend client sessions performing weight training, leaving clients to perform cardio workouts on their own. This could seem logical, especially in a society bombarded with images of what is attractive, since lifting weights may be the quickest way to improve a person's physical appearance and self-image. Plus, strength training has many functional benefits - improved muscular strength, posture and coordination; reversal of muscle tissue loss that accompanies aging; and increased bone mineral density, reducing the risk of osteoporosis. But, what about the cardio? While personal trainers help their clients get stronger and more "toned," where are they when it comes to cardiovascular endurance? Cardio endurance is arguably the most important component of health-related fitness because the functioning of the heart, lungs and circulatory system are so essential to overall health. The main problem with a lack of guidance during cardio training is that most people, when performing cardio, are not focused on what they're doing. They're listening to their iPods or reading magazines. Since research has shown that exercise intensity, rather than its volume or frequency, is more important for improving and maintaining fitness, 20 minutes of steady-state cardio at an intensity easy enough to read a magazine isn't sufficient. Personal trainers can make a big difference in this regard.

The case for cardio

According to the most recent data from the Centers for Disease Control and Prevention, 66 percent of the U.S. adult population is overweight (defined as a body mass index of greater than or equal to 25), and 32 percent is obese (defined as a body mass index greater than or equal to 30). That's a lot of fat people. There are numerous medical issues that all of this obesity is linked to, like cardiovascular disease, diabetes, cancer, gallbladder disease, menstrual abnormalities, arthritis and other orthopedic maladies, not to mention the billions of dollars it costs in healthcare. Cardiovascular disease is the No. 1 cause of death for both men and women in the U.S. While people die every day from weak hearts, no one has ever died of a weak biceps muscle. A number of studies has shown that cardiovascular (aerobic) exercise and high levels of cardiovascular fitness decrease the risk for cardiovascular disease and diabetes.^6,9,10 Indeed, people who exercise aerobically on a regular basis are half as likely to have a heart attack.¹⁰ Low cardiovascular fitness is a strong predictor of mortality from cardiovascular disease, with the risk being comparable to, or even greater than, the risk associated with other primary cardiovascular disease risk factors, including diabetes, high blood pressure (hypertension), high cholesterol and cigarette smoking.¹⁴ The number of calories expended per week in walking, stair climbing and sports has also been found to be inversely related to the development of diabetes,^6,8 the most common serious metabolic disease in the world. Hypertension is almost as big a health problem in the U.S. as obesity, affecting 58.4 million adults. While both aerobic exercise and weight training have been shown to reduce resting blood pressure,^1,2,3 aerobic exercise has a greater effect.¹¹ For the prevention, treatment and control of hypertension, the American College of Sports Medicine (ACSM) recommends that exercise programs be composed primarily of aerobic activity, supplemented by resistance exercise.¹¹ Aerobic exercise also reduces cholesterol and low-density lipoproteins (which transport cholesterol from the liver to other organs, depositing excess cholesterol in blood vessels where it can block arteries), and increases high-density lipoproteins⁴ (which remove unused cholesterol from blood vessels, bringing it back to the liver to be recycled). Conversely, weight training has not been shown to reduce blood cholesterol or improve the status of lipoproteins.³ It seems that cardiovascular exercise is the closest thing we have to a magic pill in reducing the prevalence of many of these adverse medical conditions.

Cardio is most effective

While weight training certainly has many benefits, especially for older adults, and may even reduce some cardiovascular disease risk factors, cardiovascular exercise has a greater capacity to improve overall health and fitness, decrease obesity and prevent disease. Since most of the benefits of weight training can be achieved in a relatively short period of time, the hour you spend with your clients can easily be split between both cardio and weight training. Most people simply do not need an hour's worth of weight training each session to see results. For example, research has shown that one set is just as effective as multiple sets for strength gains among beginners, with multiple sets becoming more important as people become more highly trained.^5,7,13 To increase bone mineral density, one set of a heavy load is also sufficient, as what is important is the magnitude of the stress on the bone, rather than the number of times the stress is repeated.¹⁵ For developing and maintaining muscular fitness, ACSM recommends one set of eight to 12 repetitions for eight to 10 exercises that incorporate the major muscle groups two to three days per week.¹² While average (certainly the older) clients will likely improve overall fitness by strength training because they are beginning from a low level of fitness, must every session they purchase be spent weight training? By devoting more time, both in the prescription and supervision of the cardio component of clients' exercise programs, not only will their waistlines be slimmer, they may even wait for the drive home to listen to Britney Spears.