The Short Answer
Blisters affect 80%+ of multiday runners, but they don't have to end your race. The difference between a DNF and a finish is often just proactive foot care — addressing problems before they become crises. See our best shoes for 24-hour races guide for footwear recommendations.
The Prevention Protocol
| Action | When | Why |
|---|---|---|
| Pre-tape hot spots | Before race start | Leukotape on heels, balls, toes reduces friction |
| Change socks | Every 4–6 hours | Removes moisture, resets skin environment |
| Rotate shoes | Every 6–12 hours | Accommodates swelling, changes pressure points |
| Apply lubricant | Every shoe change | Body Glide or equivalent between toes, on heels |
| Immediate treatment | At first hot spot | Drain, tape, and monitor — never ignore |
Shoe Sizing for Ultras
Your feet will swell 1–2 full sizes during a 24-hour+ event. Bring shoes in your normal race size plus 0.5 and 1.0 sizes up. Start in your normal size and switch to larger shoes when tightness begins — typically around hours 6–10.
Sources
- Hoffman, M.D. (2016) — "Foot problems in ultramarathon runners." Wilderness & Environmental Medicine, 27(4), 470–478.
- Krabak, B.J. et al. (2011) — "Foot injuries in ultramarathons." Current Sports Medicine Reports, 10(5), 295–303.