| Athletes who choose the trail over the | | | | (fat metabolism is impaired at low |
| treadmill don't get the benefit of a | | | | temperatures) by consuming up to four |
| thermostat. For much of the year in much | | | | grams of carbohydrates per pound of body |
| of the United States, they are forced to | | | | weight daily and, during exercise, |
| contend with bitter cold and sweltering | | | | feeding your muscles extra carbs (about |
| heat. But only recently have sports | | | | five to six ounces of sports drink every |
| scientists zeroed in on exactly how | | | | 15 minutes). |
| those extreme temperatures influence | | | | Brisk |
| performance. | | | | 45°F to 50°F (7°C to 10°C) |
| "The biggest breakthroughs have come in | | | | This is the sweet spot for sustained |
| the past five years," says Jim Cotter, | | | | exercise. Before long workouts, heat up |
| Ph.D., a senior lecturer at the School | | | | your muscles by jogging or cycling |
| of Physical Education at the University | | | | slowly for ten minutes and fire up your |
| of Otago, in New Zealand. "We've learned | | | | nervous system with a couple of |
| that the optimal warm-up for | | | | 30-second bursts at close-to-maximal |
| cold-weather exertion is quite different | | | | effort. During your warm-up and the |
| from the one you would carry out in the | | | | first few miles of exercise, prevent |
| heat and, perhaps more important, that | | | | shivering€”which can expend oxygen |
| the skin and brain play larger than | | | | and promote fatigue€”by wearing |
| expected roles in determining how | | | | layers that can be removed readily as |
| athletes respond to temperature | | | | you continue your workout. |
| changes." | | | | Balmy |
| The brain, scientists have discovered, | | | | 50°F to 70°F (10°C to 21°C) |
| can actually anticipate changes in body | | | | It's easier to get loose when it is 65 |
| temperature and will adjust exercise | | | | degrees (18 degrees Celsius) than when |
| intensity accordingly. This subconscious | | | | it's 35 (2 degrees Celsius). And since |
| calculation takes into account both the | | | | muscle contraction velocity increases as |
| outside temperature and the duration of | | | | sinews warm up, you can get into a |
| the effort, and explains why slowdowns | | | | groove right from the start of your |
| are almost automatic in the heat, even | | | | workout. However, when exercising for 75 |
| before signs of significant muscle | | | | minutes or more, overheating is an |
| fatigue set in. If an athlete attempts | | | | issue. One study found that marathon |
| to exercise beyond the brain's wishes, | | | | times lengthen by 19 seconds for each |
| the cerebrum will respond by generating | | | | degree above 55°F (13°C). Acclimatize |
| brutal sensations of exhaustion (i.e., | | | | by training in these temps for a week, |
| heat strain). The sad fact: Ambient | | | | and limit warm-ups to five minutes. |
| temperatures can trump your hard-earned | | | | Blazin' |
| fitness. Fortunately, though, | | | | Above 70°F (21°C) |
| researchers have developed strategies to | | | | In warm temperatures it's very difficult |
| help athletes stabilize their core temps | | | | to shed excess body heat. Studies show |
| in both hot and frigid conditions. Here, | | | | that taking an ice-cold bath or relaxing |
| scientifically backed tips to help you | | | | in an air-conditioned room prior to |
| perform optimally in four temperature | | | | exercise can up endurance by 37 percent |
| zones. | | | | for cyclists and 17 percent for runners. |
| HOW TO CONQUER ANY CLIMATE | | | | Training is important, too: When you |
| Blustery | | | | work out for a week in the heat, you |
| Below 45°F (7°C) | | | | improve blood flow to the skin, lower |
| The human body has limited physiological | | | | the skin-temperature threshold for |
| defenses for the cold. To maintain an | | | | sweating, and sweat more evenly, all of |
| optimal core temp, layer clothing | | | | which allows you to exercise at a higher |
| properly. Also, be sure that your | | | | intensity for longer. |
| muscles are well stocked with glycogen | | | | |