Temporary weight loss during ride

davidof

How much weight do you lose during a long ride? Say you weigh yourself before you start and at the end and you are 2kg light... that would be 2 liters of water sweated out right? That seems like quite a big value.

ugo.santalucia

Yes, it's about right... it depends how much you drink too... I drink very little, but others guzzle through a litre of water every 20 miles...

Dorset_Boy

The temperature and intensity of the ride will be major factors. You'll probably lose a lot more weight in 30 degrees than if it was 15 degrees. Obviously how much you then can drink is another factor.

I don't think it's uncommon for the pros to lose 4-7 kgs on some really hot tough stages.

N0bodyOfTheGoat

As above, temperature and effort greatly affect how much fluid I will get through.

On my recent ~2 hour steady rides at approx 17-20C having drank ~300ml just before leaving the house, I've coped fine with just one 750ml bottle, sometimes I've even had more than a few sips left at the ride end.

Doing a similar route but going max effort up the hills, I'd be taking out two 750ml bottles to make sure I don't run out.

When temps get to approx 25-32C, if I go out for 2-3 hours, it's two 1250ml old squash bottles and a steady ride to not run out of fluid.

I've had the odd time when I've taken a third 750-1250ml bottle attached to a seatpost cage in blazing hot weather, done a max effort up a hill or two and had to ration fluid on way home... And then guzzling plenty when I get home.

I'm simply not used to stopping at cafes/pubs for a break and a fluid top up.

Ncovidius

Most ‘instant’ weight loss is a function of dehydration mostly. If you’ve pushed yourself to the point where you end up feeding on mostly fat ( because most / all of your stored Glycogen has depleted ) you could see some genuine weight loss, but it won’t be drastic, unless you’ve put yourself in A&E.

davidof

Ncovidius said:

you could see some genuine weight loss, but it won’t be drastic, unless you’ve put yourself in A&E.

singleton

Sweat rate is dependant on our unique metabolism but can be up to 3 or 4 litres per hour in the right (wrong) conditions.

pblakeney

Metabolisms change too. I rarely used to sweat and only took water bottles if I was doing a long or strenuous effort. Then i overcooked on a day in the Alps and the sweat taps opened.
They’ve not shut since and now I need to take a bottle per hour, even in winter.

Ncovidius

pblakeney said:

Metabolisms change too. I rarely used to sweat and only took water bottles if I was doing a long or strenuous effort. Then i overcooked on a day in the Alps and the sweat taps opened.
They’ve not shut since and now I need to take a bottle per hour, even in winter.

This is a very pertinent point. As we age, things change. You need to be able to adjust accordingly.

orraloon

pblakeney said:

Metabolisms change too. I rarely used to sweat and only took water bottles if I was doing a long or strenuous effort. Then i overcooked on a day in the Alps and the sweat taps opened.

Have a word with Prince Nonce. 😉

Ncovidius

orraloon said:

pblakeney said:

Metabolisms change too. I rarely used to sweat and only took water bottles if I was doing a long or strenuous effort. Then i overcooked on a day in the Alps and the sweat taps opened.

Have a word with Prince Nonce. 😉

It’s a ‘medical issue’ he got it during the falklands conflict ( allegedly).

katani

Dorset_Boy said:

The temperature and intensity of the ride will be major factors. You'll probably lose a lot more weight in 30 degrees than if it was 15 degrees. Obviously how much you then can drink is another factor.

I don't think it's uncommon for the pros to lose 4-7 kgs on some really hot tough stages.

For a 65kg rider that's 7%-11%. 5% equals drop in performance by 30%, at 7% is a hallucinations territory, 10% is circulatory collapse combined with heatstroke or even death.