Olympic | Total n=100 (%) | Minor degree | Moderate degree | Severe degree | P value | |||||
n=50 (%) | n=40 (%) | n=10 (%) | ||||||||
Patient factor | ||||||||||
Gender* | Male | 54 | (54.0) | 27 | (27.0) | 23 | (23.0) | 4 | (4.0) | 0.84 |
Female | 46 | (46.0) | 23 | (23.0) | 17 | (17.0) | 6 | (6.0) | ||
Age† | 20s | 69 | (69.0) | 28 | (28.0) | 35 | (35.0) | 6 | (6.0) | 0.003 |
30s | 30 | (30.0) | 21 | (21.0) | 5 | (5.0) | 4 | (4.0) | ||
40s | 1 | (1.0) | 1 | (1.0) | 0 | (0.0) | 0 | (0.0) | ||
Home continents† | European | 37 | (37.0) | 22 | (22.0) | 9 | (9.0) | 6 | (6.0) | |
American | 28 | (28.0) | 9 | (9.0) | 17 | (17.0) | 2 | (2.0) | ||
Asian | 20 | (20.0) | 8 | (8.0) | 11 | (11.0) | 1 | (1.0) | ||
African | 11 | (11.0) | 10 | (10.0) | 1 | (1.0) | 0 | (0.0) | ||
Oceanian | 4 | (4.0) | 1 | (1.0) | 2 | (2.0) | 1 | (1.0) | ||
Environment factor | ||||||||||
Venue zone† | Tokyo bay zone‡ | 27 | (27.0) | 4 | (4.0) | 18 | (18.0) | 5 | (5.0) | <0.0001 |
Heritage zone§ | 22 | (22.0) | 5 | (5.0) | 17 | (17.0) | 0 | (0.0) | ||
Sapporo Odori Park (marathon/race walk) | 50 | (50.0) | 41 | (41.0) | 4 | (4.0) | 5 | (5.0) | ||
Other venue (Kasumigaseki Country Club) | 1 | (1.0) | 0 | (0.0) | 1 | (1.0) | 0 | (0.0) | ||
Location* | Outdoors venue | 100 | (100.0) | 50 | (50.0) | 40 | (40.0) | 10 | (10.0) | 0.00 |
Indoors venue | 0 | (0.0) | 0 | (0.0) | 0 | (0.0) | 0 | (0.0) | ||
Time† | Morning game (7:00 to 12:00) | 58 | (60.0) | 33 | (33.0) | 16 | (16.0) | 9 | (9.0) | 0.29 |
Afternoon game (12:00 to 18:00) | 26 | (23.0) | 12 | (12.0) | 13 | (13.0) | 1 | (1.0) | ||
Evening game (18:00 to 22:00) | 17 | (17.0) | 6 | (6.0) | 11 | (11.0) | 0 | (0.0) | ||
WBGT (°C)* | 21°C<WBGT<28°C | 49 | (49.0) | 29 | (29.0) | 16 | (16.0) | 4 | (4.0) | 0.05 |
28°C≤WBGT | 51 | (51.0) | 21 | (21.0) | 24 | (24.0) | 6 | (6.0) | ||
Sports factor | ||||||||||
Athletic classification* | Endurance sports | 72 | (72.0) | 43 | (43.0) | 19 | (19.0) | 10 | (10.0) | 0.002 |
Non-endurance sports | 28 | (28.0) | 7 | (7.0) | 21 | (21.0) | 0 | (0.0) | ||
Endurance sports | Athletics (marathon/race walk) | 50 | (50.0) | 41 | (41.0) | 4 | (4.0) | 5 | (5.0) | |
Rowing | 10 | (10.0) | 0 | (0.0) | 7 | (7.0) | 3 | (3.0) | ||
Tennis | 5 | (5.0) | 1 | (1.0) | 3 | (3.0) | 1 | (1.0) | ||
Marathon swimming | 2 | (2.0) | 0 | (0.0) | 2 | (2.0) | 0 | (0.0) | ||
Cycling | 1 | (1.0) | 1 | (1.0) | 0 | (0.0) | 0 | (0.0) | ||
Triathlon | 2 | (2.0) | 0 | (0.0) | 2 | (2.0) | 0 | (0.0) | ||
Beach volleyball | 1 | (1.0) | 0 | (0.0) | 0 | (0.0) | 1 | (1.0) | ||
Hockey | 1 | (1.0) | 0 | (0.0) | 1 | (1.0) | 0 | (0.0) | ||
Non-endurance sports | Athletics (track and field) | 20 | (20.0) | 4 | (4.0) | 16 | (16.0) | 0 | (0.0) | |
Archery | 3 | (3.0) | 2 | (2.0) | 1 | (1.0) | 0 | (0.0) | ||
Equestrian | 2 | (2.0) | 1 | (1.0) | 1 | (1.0) | 0 | (0.0) | ||
Golf | 1 | (1.0) | 0 | (0.0) | 1 | (1.0) | 0 | (0.0) | ||
Canoe sprint | 1 | (1.0) | 0 | (0.0) | 1 | (1.0) | 0 | (0.0) | ||
Sport climbing | 1 | (1.0) | 0 | (0.0) | 1 | (1.0) | 0 | (0.0) | ||
Treatment factor | ||||||||||
CWI | 6 | (6.0) | 0 | (0.0) | 0 | (0.0) | 6 | (6.0) | ||
Intravenous injection | 5 | (5.0) | 0 | (0.0) | 4 | (4.0) | 1 | (1.0) | ||
Ice towel | 35 | (35.0) | 15 | (15.0) | 18 | (18.0) | 2 | (2.0) | ||
Ambulance transportation | 4 | (4.0) | 1 | (1.0) | 1 | (1.0) | 2 | (2.0) | ||
Hospitalisation (<2 days) | 0 | (0.0) | 0 | (0.0) | 0 | (0.0) | 0 | (0.0) |
Endurance sports: athletics (marathon/race walk), cycling and marathon, swimming, tennis, rowing, triathlon, beach volleyball and hockey; non-endurance sports: athletics (track and field), sport climbing, archery, equestrian, golf and canoe sprint.
*Between the group; in the Ⅰ degree and Ⅱ degree/Ⅲ degree Fisher's exact probability test.
†Among the group; in the Ⅰ degree and Ⅱ degree/Ⅲ degree Fisher's exact probability test.
‡Tokyo Bay Zone; Aomi Urban Sports Park, Oi Hockey Stadium, Shiokaze Park, Ariake Urban Sports Park, Yumenoshima Park Archery, Odaiba Marine Park, Ariake Tennis Park, Sea Forest Waterway.
§Heritage Zone, Olympic Stadium & Equestrian Park.
CWI, cold water immersion; WBGT °C, wet-bulb globe temperature occurred at heat-related illness.