After 41 marathons I have a formula that works for me most of the time. Take it for what it's worth. It has four components:
- Salt; and
Hydration: According to my own weight measurements before and after running, my body uses about 5 ounces of water per mile, more when it's hot. However, according to Noakes, my system will probably only absorb about 2 1/2 ounces of ingested water per mile. When aid stations are spaced about two miles apart, one 5-ounce cup at every station usually works well.
Salt: In my last marathon I ran at about the same pace as a small Team In Training group that was shepherding a young runner through his first complete marathon. Calf cramps had prevented him from finishing a previous attempt. For some reason, though, no one had thought to bring salt. He did finish, but he had to fight through some serious cramps. I wished I had enough salt to share.
Salt makes a BIG difference for me. I have been using electrolyte tablets from a medical supply company, containing about 180 mg of elemental sodium (about 450 mg salt) per packet, plus a little potassium. According to Noakes, a runner uses at least 400 mg elemental sodium (1000 mg salt) per hour, but may not need to replace all of it. I take one packet about every second water stop, or about every four miles, and at my pace that is usually at least 500 mg salt, equivalent to at least 200 mg elemental sodium, per hour. It seems to work.
Unfortunately, the tablets that I currently use are no longer sold. It's too bad, because each tablet is packaged in its own tiny sweat-proof wrapper, so I can just throw a half-dozen in my pocket and fish them out one at a time as needed. When these run out, here are some candidates:
- Succeed S!Caps. More than twice as large as the packets I'm taking now, so I'd take fewer.
- Thermotabs. Virtually identical to the tablets I'm taking now, 180 mg elemental sodium and a little potassium per tablet.
- Lannett Buffered Salt Tabs. Also virtually identical to the tabs I now take, 180 mg elemental sodium per tab. I suspect this is the same product as Thermotabs, with a different label.
Stretches: We should stretch after every run for several reasons, and I think that cramp prevention is one of them. I find it very helpful indeed to stretch calf muscles right away after a 20-mile run or a marathon to prevent the cramps that can occur then. Sometimes, in fact, I have to stop and stretch during a race just to get to the end.
Please add comments with your own advice, if you like.