Cycling UK Forum

Last week I went out and had a run over the Cat and Fiddle in Derbyshire. I'd checked my weight before I went out 15st 4lb which is pretty constant, on return I checked again, 14st 9lb. 9lb loss in 4hrs. Yesterday I had a run to Chester and back start weight 15st 4lb, weight on return 14st 11lb, 7lb loss in 6hrs. I took water with me on both occasions. On the first ride I didn't drink much although it was very hot, on the second ride I took the same amount (two bottles) and drank most of it.
Would this be considered normal or excessive.

I checked my weight again this morning and it's 14st 11lbs

Malc

I don't think the weight change is that excessive, it's just a few percent of body weight. I used to weigh about the same any my weight would fluctuate quite a bit day to day.
2 bottles (2l?) of water doesn't seem much to drink, I'd drink more than that in 6hrs without the cycling.

Greg

Agree with water intake. Just got back from a tour in Western France where the temperature has been 25-30c, and I was drinking 6-8 litres per day and the pee was still dark yellow.

Your weight can vary by 4-5lbs naturally from day to day and even within the day (obvious stuff like eating food, how much activity etc.). I wouldn't be too concerned about it. Just keep hydrated and eat properly.

EDIT: as previously mentioned, if those two bottles are all you drank, then you're most likely quite dehydrated. Top up.

The other thing to bear in mind is that your glycogen stores - in your muscles and liver - have about 3 times as much water by weight associated with it. Running down your glycogen resources by exercising (such as riding up the Cat & Fiddle ) will result in weight loss even if you maintain your hydration. Looking around it looks like the human body stores about 600g of Glycogen (example in introductory paragraph). You can therefore potentially have lost 2-2.5kg (4.5-5lb) just by your glycogen stores getting completely depleted.

A bit of dehydration too could easily account for the remainder of the loss.

As an aside, the depletion of glycogen plus associated water loss is, I believe, one of the reasons that crash (fad?) diets appear to work initially but then tail off (as well as changes in metabolism as the body adapts to its "lean" diet).

Rick.

RickH wrote:The other thing to bear in mind is that your glycogen stores - in your muscles and liver - have about 3 times as much water by weight associated with it. Running down your glycogen resources by exercising (such as riding up the Cat & Fiddle ) will result in weight loss even if you maintain your hydration. Looking around it looks like the human body stores about 600g of Glycogen (example in introductory paragraph). You can therefore potentially have lost 2-2.5kg (4.5-5lb) just by your glycogen stores getting completely depleted.

A bit of dehydration too could easily account for the remainder of the loss.

As an aside, the depletion of glycogen plus associated water loss is, I believe, one of the reasons that crash (fad?) diets appear to work initially but then tail off (as well as changes in metabolism as the body adapts to its "lean" diet).

Rick.

There's an element of truth in that, but much less than people think. E.g. on a ketogenic (very low carb high fat) diet, the muscle glycogen is still 70% of what it would be on a high carb diet. The weight loss on such a diet can still be fairly spectacular.

I see that sort of weight loss on a ride. I think it's hard to replace the amount of fluid whilst out on a ride. You can tell if you're dehydrated by the colour of your urine. if well hydrated, it should be straw coloured. If it's dark yellow then you're dehydrated. i find i return to normal weight and hydration level a couple of days after a longish ride.

LUCKY YOU

I believe that body weight may fluctuate day to day by 4-5lbs, particularly when exercising, due water loss. Hope this information helps.