Anaerobic Exercise
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Anaerobic Exercise

"Unless you're training for a marathon, bike race, or triathlon," says Rodolpho "Rudy" Reyes, "cardio is an inefficient waste of a guy's valuable time." By "cardio," he means aerobic exercise of the sort that has been standard practice for years – the tried-and-true hour on a treadmill, say, or an elliptical machine: low-intensity, steady-state work with oxygenated blood. Before you dismiss Reyes's notion outright, or cling to the conventional wisdom that pounding the pavement for 60 minutes is the only way to stay fit and trim, consider the source – then consider a growing body of science that backs him up.

A former Recon Marine sergeant, Reyes, 36 (pictured), served two tours in Iraq and one in Afghanistan. His physique and robust health prove what fitness can do for a man when long jogs in enemy territory aren't an option. At 5 feet 11 inches tall, and 175 pounds with only 4 percent body fat, he looks like a Greek sculpture, and the last time he did any type of sustained aerobic exercise was when he raced an Xterra off-road triathlon (1-mile swim, 19-mile mountain-bike ride, 16-mile run) in 2006. To train for that event, he ran sprints and lifted weights instead of doing cardio, and he finished a respectable 41st in his age group. Now a fitness promoter and actor in San Diego County, he advocates a variety of 20-to-30-minute sprint and circuit exercises – including weightlifting and martial arts – which will raise your heart rate 25 to 30 beats higher per minute than a five-mile jog or a 30-mile spin and leave you far more spent. He does explosive body-weight lifts and a mix of jujitsu and other martial arts training.

"If your definition of fitness is keeping fat off, having a stronger heart, and being able to endure rigorous activity, like a day of skiing," says Nick Delgado, president of Newport Beach, California-based Ultimate Medical Research, "then you want to be doing anaerobic exercise." As opposed to aerobics, this type of exercise involves maximum-effort training, such as sprinting and lifting weights, in which the intensity of the exercise exceeds the body's ability to supply oxygen to muscles. "Shorter, high-intensity workouts burn off glucose much faster than long runs, so you start burning fat at a much higher rate, your heart beats so hard that it becomes stronger, and you're pushing yourself to such extremes that anything else you do feels easier," says Delgado.

Not convinced? Consider a 2007 study by Canada's McMaster University's kinesiology department that found, in addition to the known benefits of gains in strength and bone density, that resistance training (such as body-weight squats and pushups) reduces one's risk for diabetes and cardiovascular disease. That's because even moderate strength training may significantly lower unhealthy levels of cholesterol and triglycerides, two main causes of heart disease. And the increase in muscle mass spurs loss of fat and lowers blood glucose, which are both causes of diabetes.

Even in terms of sports performance, endurance training is no longer seen as the key to being a better athlete. A study conducted on Division-1A baseball players, published last January in the 'Journal of Strength and Conditioning Research,' found that those who did eight 20-to-30-second wind sprints (which rely on the same anaerobic systems used in strength training) three days a week, saw their power increase by an average of 15 percent over the course of a season. Players who did the team's conventional, moderate-intensity routine (45 minutes of running or cycling, three or four days a week) actually found their power dropped an average of 2 percent

And it's not just athletes involved in power sports like baseball who benefit from heavy doses of anaerobic activity. Programs like CrossFit and Nike SPARQ use circuit training to prepare athletes for long games like soccer and tennis; Mark Twight's Gym Jones uses a similar technique to train mountaineers and skiers; and Chris Carmichael, Lance Armstrong's coach, has been prescribing interval workouts for certain cyclists, runners, and triathletes for years. "The less time an athlete has to train, the more I prescribe a routine of short, 30-second-to-two-minute, all-out efforts to build speed and power," says Carmichael. "This kind of training taps an athlete's VO2 max, or top-end aerobic capacity, and improvement at the top of the scale yields better performance at all the aerobic levels below it. A guy's not going to win the Tour de France with this kind of training, but I have middle-aged, career-focused dads winning hour-long bike races and 10-K runs using this time-efficient, high-intensity training."

Despite evidence that anaerobic exercise seems to be a smarter approach to training, many have been slow to embrace it because of the long-held idea that aerobic training is a better overall workout.

Lou Schuler, who has followed trends in fitness and training for close to three decades and authored 'The New Rules of Lifting: Six Basic Moves for Maximum Muscle,' disagrees. "One reason the medical society is so hung up on cardiovascular exercise is due to Dr. Kenneth Cooper, who made the idea of 'aerobic fitness' mainstream when he published his bestseller 'Aerobics' in 1968," he says. "What people missed is that Cooper's work focused on cardiovascular health, not whole-body fitness. But that didn't stop the supposed health experts from making aerobics the be-all, end-all fitness and weight-loss panacea."

Following the success of Cooper's book, scientists jumped on the bandwagon and started testing all sorts of aerobic exercises to see if they helped reduce the risk of disease and prolonged life. In the meantime, strength training was banished to the wasteland of muscleheads, grunting through sets. It was what a guy did to get huge, but not necessarily get fit or lose weight. Still, cautions Dr. Edward Laskowski, co-director of the Mayo Clinic's Sports Medicine Center, there are "four pillars" of fitness: aerobic capacity, strength, range of motion, and stability. "Trying to combine all of them into one [as many of Reyes's workouts do] means you lose out on something," he says. "You can't squat your max while standing on a physio ball, and you won't build cardiovascular stamina doing core strength exercises. That's not to say there's no cardiovascular benefit to lifting weights, but the literature points to the idea that strength training can't supplant aerobic exercise."

Nonetheless, Schuler believes, "We went too far to the cardio side. It's time to swing back the other way. Even the medical establishment recognizes that a major determining factor in longevity is a person's muscle strength, not his capacity to run marathons."

"You need muscle to move," explains 78-year-old Dr. Walter Bortz, clinical associate professor of medicine at Stanford University School of Medicine and the author of 'Dare to Be 100.' "Simply put: If you can't move, you grow frail. Grow frail, you die."

No one knows this better than Reyes. During a clandestine mission in Fallujah he spent a night hanging under a bridge by his heels, hands, and sometimes his chin, while stealthily placing 100 pounds of explosives and detonators on the span. "I couldn't have succeeded without my type of fitness," he says. "Running marathons wouldn't have given me the stamina to haul those explosives up there." But it wasn't on the battlefield that his fitness was tested most; it was at home last winter when his vehicle was broadsided while going 60 mph on a highway. His car flipped into oncoming traffic and rolled multiple times before coming to rest on its roof. "I was totally aware of what was going on," says Reyes. "When the car stopped, I unbuckled myself, kicked out the rear window, and walked away with minor scrapes and bruises.

"I know I can credit my surviving that crash to my fitness," he says. "I doubt a skinny dude who just runs all the time would've survived. So, when someone describes a lean and lanky runner or cyclist as fit, I can look them straight in the eye, and say: No, they're not."

See also: The New Treadmill Workout