corrodgery wrote:Should I be drinking water or gatorade or sport drink?
Jon Mortimer wrote:It's a con. "Sports drinks" is a soft drink manufacturer's marketing niche. If you are planning to quickly sprint the 60 to 80km each day without stopping for food or rest then I'll concede that you will need something in the bottle other than water. Muscle glycogen will run out between 90 and 120 minutes. However, I'd rather ride at somewhat less than "tour de France" pace and get my energy from real food at breakfast, morning tea and lunch. Happy to ride a century but have never put anything in my water bottles other than water.
With the money saved buy a banana.
There has been some undeserved publicity about the negative effect of eating in the hour before exercise. One study published in 1979 showed that the ingestion of 75g of glucose 30 minutes before exercise impaired sub-maximal cycling endurance time. The pre-exercise feeding elevated blood glucose and insulin, and suppressed blood free fatty acids at the start of exercise. As the exercise progressed blood glucose fell in the feeding trial and fat oxidation was lower than in the fasting control trial. Some researchers call this phenomenon "rebound hypoglycaemia" and is characterized by nausea, dizziness, "the shakes", and premature fatigue. The results of this study were widely reported and warnings given to athletes to avoid carbohydrate intake in the hour before exercise. In the dozen or so studies since, however, there was no evidence for a decline in performance following carbohydrate feeding in the hour before exercise. In fact, about half of these studies found evidence for improved performance. Furthermore, in most cases rebound hypoglycaemia can be offset with the ingestion of food or a carbohydrate sports drink during exercise. Nevertheless, some athletes are hypersensitive to the effects of carbohydrate ingested in the hour before exercise. These athletes experience a rapid drop in blood glucose, hypoglycaemic symptoms, and increased carbohydrate usage from the onset of exercise. If you are one of these athletes you can try:
• low glycemic index carbohydrate foods which result in a less aggressive blood glucose and insulin response (e.g. porridge, chocolate, apples, pasta, beans or lentils, milk)
• experimenting with timing your eating to avoid the blood sugar low
• a thorough warm up; adrenaline stimulates release of glucose from the
liver and lowers blood insulin concentration
• adding more easily digestible fat (e.g. butter, monounsaturated oils or spreads) to your pre-exercise meals; you may be surprised There has been quite a bit of interest in recent times regarding the effect of meal
glycemic index (GI) on metabolism and endurance performance. Essentially, the GI reflects the rate of digestion and absorption of carbohydrate in a meal. Low GI foods and drinks cause a slower and more sustained change in blood glucose and insulin concentrations than eating the same amount of carbohydrate from foods with a high GI.
It has been proposed that eating meals with a low GI could benefit performance because of the less aggressive insulin and the smoother blood glucose and free fatty acid responses. There are two studies providing some evidence to suggest an improvement in endurance performance with a low GI compared with a high GI meal, but the results
from the remaining half dozen or so other studies to date suggest there is no real effect of GI. Furthermore, if carbohydrate sports drinks are taken during the exercise, any difference in metabolism and performance in
response to the meals is largely smothered by the effects of the sport drink. In summary, there could be some benefit of pre-exercise low-GI meals for some triathletes who a particularly sensitive to carbohydrate, but in most, the effects of pre-exercise highcarbohydrate meals on blood glucose, fatty acids, and insulin are transient and offset by the increased carbohydrate availability.
twowheels wrote:If the exercise is of less than 1 hr duration, I would suggest just water, unless your a very heavy sweater or exclude salt from your diet.
Over the hour, certainly replace what you lose, hard to tell, but if I can taste salt on my lips, i clean out the bottle.
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