Which Comes First, Cardio or Weights_ - Alex Hutchinson [58]
Will a heat pack or hot bath soothe my aching body?
Nowhere are the healing powers of a hot bath more respected than in Japan. Researchers there have found, for example, that levels of the stress hormone cortisol drop after a relaxing soak in the tub. Heat is also prescribed for conditions ranging from arthritis to chronic pain. But when it comes to exercise and athletic injuries, heat isn’t always the right choice.
The traditional advice has been to apply cold to acute injuries—a sprain or a bruise, for example—and reserve heat for nagging pains that persist for weeks or months. The reason is that new injuries are often accompanied by swelling. Cold constricts your blood vessels to limit swelling, while heat can have the opposite—undesirable—effect. Chronic injuries, on the other hand, are often tight and surrounded by scar tissue, so heat can help soften and loosen the muscles around the injury, allowing them to move more freely.
Researchers believe that to have a significant loosening effect on muscle, the heat needs to increase skin temperature by 5 to 7°F (3 to 4°C) for about five minutes. The problem is that when you put a heat pack next to your skin, the greatest heating effect is limited to the outer quarter-inch of your body. Even just an inch below the surface, a heat pack generally elevates muscle temperature by less than 2°F. Electric blankets, hot water bottles, saunas, and even hot baths also qualify as “superficial” heat sources that don’t penetrate far into your muscles. (Heating deeper tissue generally requires machines using, for example, ultrasound, shortwave, or microwave energy. Several studies have found that shortwave machines can produce muscle temperature changes of over 7°F at a depth of greater than an inch.)
So does heat work? According to a 2010 literature review by the Cochrane Collaboration, there is “moderate evidence in a small number of trials” that heat wraps can reduce lower-back pain. For example, a pair of studies found that after five days of using a heat wrap, subjects reduced their back pain by 17 percent compared to subjects who were given a placebo pill instead. This gives some credence to the idea that you might get some relief from nagging aches throughout the body by applying a heat pack, or even by soaking in the tub.
But the more common and well-supported use for heat is immediately before exercise, to help prepare an injured or (preferably) recovering muscle for further exertion. Just as a proper warm-up helps to ensure that your muscles and tendons are loose and supple, focused heat at the site of a nagging injury can make sure the affected muscles are as warm as possible before you start using them. A 2005 study in the Archives of Physical Medicine and Rehabilitation found that pre-heating calf muscles with a heat pack allowed greater ankle flexion, even without any additional stretching. The heat pack in this case started at about 175°F (80°C) and was applied for 15 minutes; towels between the pack and the subject’s skin ensured that it didn’t exceed “comfortably warm.” As expected, deep heating using a shortwave machine produced even greater increases in flexibility.
Overall, the clinical evidence on the use of heat suggests a few guidelines: use it before exercise rather than after, and don’t use it on a fresh injury. Beyond that, the evidence is thin enough that it comes down to personal preference. It won’t hurt you, and—as the Japanese researchers have shown—it might make you feel better.
Will massage help me avoid soreness and recover more quickly from workouts?
There’s one big problem with studying the effectiveness of massage: you can’t control for the placebo