There isn't an exact prescription without knowing your sweat rate (in L/hr) and sweat concentration (mg sodium/L). But if you are like me, who is a little bit above average in sweat rate and concentration, you should probably aim for 700-1000mg / hr of sodium replacement (in hot weather) and 1-1.5L of fluid per hour. To put in perspective I lose about 2kg (~5lb) per hour running in hot weather.

So with your example below, if the bottle contains 687mg of sodium (is the bottle 1L?), you might aim for 1.5 bottles per hour. If it is less than that you would take a salt pill to get to that ~1000mg/hr replacement rate.

---

Strava

sch340's answer was good.

But I'll add that you should get sodium tested. Here are a few links of where you can do that:
https://sweattracker.tadabase.io/...racker#!/sodium-loss

Once you know your sodium loss, test your sweat loss under similar conditions. You can track your sweat loss here: https://sweattracker.tadabase.io/sweat-tracker#!/home

If you still can't do that, aim for 800-100mg of sodium per litre of sweat you lose. If you're a heavy sweater, you could lose up to 2 litres per hour.

If in doubt, take more than you need - it won't hurt you.

---

101Ironman Hacks & Newsletter: http://ironmanhacks.com/newsletter/

YouTube interviews with legends like Mark Allen, Dave Scott, many more: https://www.youtube.com/...s?sub_confirmation=1