Which Comes First, Cardio or Weights_ - Alex Hutchinson [30]
CHEAT SHEET: THE PHYSIOLOGY OF EXERCISE
• Your physical limits aren’t defined by the failure of your muscles, heart, or lungs; instead, there’s increasing evidence that “fatigue” is regulated by subconscious processes in the brain.
• Lactic acid isn’t a metabolic waste product that makes your muscles burn. It’s actually a useful fuel that provides energy to your muscles; the fitter you are, the more lactic acid you use.
• Hard exercise causes microscopic damage to your muscle fibers. The repair process causes swelling and hypersensitive nerve endings, leading to “delayed onset muscle soreness” (DOMS) that peaks a day or two later.
• VO2max is a measure of the maximum amount of oxygen you can deliver to your muscles during exercise. It’s a measure of aerobic fitness but varies widely even among athletes of equal ability.
• “Lactate threshold” refers to the point at which lactate begins to accumulate rapidly in your blood, indicating that you’re no longer in the “aerobic” zone. It’s often used to monitor the progress of training.
• Moderate exercise boosts your immune system, but very intense exercise—serious marathon training, for example—can temporarily suppress it.
• Muscle cramps are traditionally blamed on electrolyte loss through sweat, but a new theory suggests that they’re caused by disrupted neural reflexes linked to muscular fatigue.
• “Stitches” are still poorly understood but may result from friction between layers of a membrane lining the abdominal cavity. Good posture reduces your chances of getting one.
• Peak physical performance for most people occurs in the late afternoon or early evening, around 6 p.m., when body temperature is highest. You can boost your performance at a particular time of day by training regularly at that time.
Chapter 4
Aerobic Exercise
EXERCISE FADS COME AND GO—and sometimes come again, like the trampoline craze that flourished in the 1950s, faded from view, then roared back with the introduction of mini-trampolines in the late 1970s. But the basic elements remain unchanged: sustained rhythmic exercise is the most important element in any general fitness program, whether you call it cardio (because it strengthens your heart and circulatory system) or aerobic exercise (because it requires oxygen).
The term aerobics was only coined in 1968, when Air Force researcher Kenneth Cooper published a best-selling book of that name, and originally referred to any exercise with aerobic benefits (not just 80s-style classes filled with colorful spandex). That versatility is important to remember: once you learn to judge your effort appropriately, you get a good aerobic workout just about anywhere—inside or outside, at the gym or on the way to work . . . and even on a trampoline.
Why should I do cardio if I just want to build my muscles?
Slogging away on an exercise bike will never give you bigger biceps or a faster fastball, no matter how hard you pedal. So there’s a temptation to focus your workout efforts on the goals you’re most interested in and neglect the rest—especially if you don’t particularly enjoy cardio workouts. Whether you’re focused on health or athletic performance, this is a bad idea.
Aerobic fitness is often assessed by measuring how much oxygen you can breathe in and deliver to your muscles when working as hard as you can, a quantity known as VO2max (see Chapter 3). You can improve aerobic fitness by doing activities that continuously use large muscle groups—walking, running, biking, step aerobics, swimming, dancing, and so on. These activities are sometimes lumped together as “cardio” exercises because they improve the health of your cardiorespiratory system—your heart and lungs.
The adaptations that result from aerobic exercise—strengthening the heart, increasing the number of small arteries