Purpose:

Recent studies suggested that women’s and men’s ultraswim performances may be similar for distances of ~35 km. The current study investigated both the gender difference and the age of peak ultraswim performance between 1983 and 2013 at the 46-km Manhattan Island Marathon Swim with water temperatures <20°C.

Methods:

Changes in race times and gender difference in 551 male and 237 female finishers were investigated using linear-, nonlinear-, and hierarchical multilevel-regression analyses.

Results:

The top 10 race times ever were significantly (P < .0001) lower for women (371 ± 11 min) than for men (424 ± 9 min). Race times of the annual fastest and annual 3 fastest women and men did not differ between genders and remained stable across years. The age of the annual 3 fastest swimmers increased from 28 ± 4 y (1983) to 38 ± 6 y (2013; r2 = .06, P = .03) in women and from 23 ± 4 y (1984) to 42 ± 8 y (2013; r2 = .19, P < .0001) in men.

Conclusions:

The best women were ~12–14% faster than the best men in a 46-km open-water ultradistance race with temperatures <20°C. The maturity of ultradistance swimmers has changed during the last decades, with the fastest swimmers becoming older across the years.