Wednesday, February 13, 2008
The New Cause of Muscle Fatigue: Calcium Leakage & How to Manage Cramps
The causes of muscle fatigue are elusive. For more than 80 years, physiologists blamed lactic acid, which is produced during exercise and which they believed interfered with muscles' contractile proteins. That's what we've all been told, right?....But in the early 2000s, researchers found that at realistic body temperatures, very little acid accumulates inside muscle cells--and the bit that does may even improve endurance. Physiologist Andrew Marks of Columbia University has completed a study suggesting overdoing it may temporarily sap muscles of calcium and strength. The findings might do more than explain why muscles need rest after intense training. Marks' team put mice on an intense training regimen that included scampering along a treadmill. During high-intensity exercise, the mice's muscles leaked calcium, and when that happened, the mice's muscle endurance nose-dived. Their muscle strength recovered with three days of rest. Humans showed similar changes. When the team analyzed the calcium-channel structure in muscle samples from 12 elite athletes before and after a series of intense cycling sessions, their calcium channels had begun to undergo changes that were "totally parallel" to what had happened in the mice, Marks says. "exhausting exercise, such as that performed by a marathon runner results in significant muscle damage and can impair task performance for days or weeks." Here's a more comprehensive read on the same study, and the New York Times has also written about the study here. On a similar note Jane Clarke, a nutritionist gave the most comprehensive insight on how to manage cramps I've read in a while and explains why you commonly see Bananas being served at races after the event, and offered to runners by fans during marathons, it goes beyond potassium too. She says, " cramps can be hugely debilitating. It is also not uncommon for cramps to ease up and then return several times before going away entirely. Many fitness experts think cramps are related to poor flexibility, muscle fatigue or doing a new activity. Other factors include exercising in extreme heat, dehydration and electrolyte depletion. Electrolytes are nutrients such as sodium or salt, potassium, magnesium and calcium, which are sweated out during exercise. When levels of these nutrients - important for everything from muscle movement to blood pressure - drop, you suffer more muscle spasms. Sipping water (or an electrolyte-filled sports drink) is therefore vital throughout a training session. Again, the causes are not fully understood, however certain conditions such as iron deficiency, anaemia, smoking, hormone imbalances, varicose veins, arthritis, even atherosclerosis (blocked arteries) can all result in cramping and tend to be more prevalent in older people. Medication such as diuretic drugs for high-blood pressure or heart disorders can cause cramps, as can poor circulation, so see your doctor to ensure everything is OK. But if none of the above applies to you, your cramps could be down to an imbalance in the body's electrolytes - magnesium, calcium and potassium - and/or deficiency of vitamin E. To boost magnesium levels, try including more pulses, tofu, nuts, potatoes and oatmeal in your diet. Lack of calcium can also aggravate night cramps. Ordinary calcium sources include leafy green vegetables, small-boned fish such as sardines, orange juice, cereals and nuts. To boost your potassium intake, eat bananas, pulses, garlic and onions, and fruit and vegetables in general. Make sure your diet is rich in vitamin E - this includes vegetable oils, nuts, seeds, avocados and sweet potatoes. On that note I'm going out to try and clock 5 miles in the snow - assuming the roads are not too icy...have a great day!
Posted by Smith at 6:12 AM