80% of People Recognize the Need for Heatstroke Measures in the Rainy Season! Yet, Many Still React Only to 'Summer Heat and Thirst'—Warning Against Hard-to-Detect 'Rainy Season Heatstroke'

Fine Japan Co., Ltd. (Headquarters: Yodogawa-ku, Osaka; CEO: Nobutsuna Sasaki), a manufacturer and seller of health foods and pharmaceuticals, conducted an awareness survey on 'Heatstroke Prevention and Hydration During the Rainy Season' targeting 402 men and women in their 20s to 50s nationwide.

The results revealed that while about 80% of respondents believe caution is necessary even during the rainy season, the most commonly imagined scenario for heatstroke was 'being outdoors under the strong summer sun.' Furthermore, although nearly 60% cited 'staying hydrated' as their primary heat measure, the most frequent timing for hydration was 'when feeling thirsty,' showing that early and frequent replenishment has not yet fully permeated daily habits.

During the rainy season, high humidity makes it difficult for sweat to evaporate. While it may not feel as intense as the peak summer heat, the burden on the body can be significant. Therefore, it is crucial to focus on proactive hydration before feeling thirsty.

### Survey Summary

**TOPIC 1: Recognition of the Need vs. Gap in Action** - Approximately 80% of respondents feel the need for heatstroke measures during the rainy season. - However, the dominant image of heatstroke remains 'outdoors under strong summer sun' (48.3%). - Indoor risks during the rainy season are often overlooked, creating a gap between awareness and actual prevention.

**TOPIC 2: Reactive Hydration Habits** - Hydration is the most common countermeasure (59.3%). - Yet, 'when feeling thirsty' is the primary trigger for drinking, which is a reactive approach. - According to Ministry of the Environment data, people may not feel thirsty in mild dehydration states, especially in low-wind or high-humidity environments.

**TOPIC 3: Importance of 'How' and 'When' to Hydrate** - 'Frequent drinking' is well-practiced, but drinking 'before feeling thirsty' and 'replenishing salt/minerals' remain at about 30%. - During the rainy season, both the timing and the content of hydration (not just water, but also minerals) are essential.

### Survey Details

- **Method:** Internet survey - **Dates:** May 7 (Thursday) to May 10 (Sunday), 2026 - **Participants:** 402 men and women aged 20–59 nationwide

**Analysis of TOPIC 1:** When asked if they thought heatstroke prevention was necessary during the rainy season, 75.9% answered affirmatively. However, the scenarios most associated with heatstroke were 'outdoors in summer' (48.3%) and 'high-temperature outdoor activities' (42.3%). This suggests that while awareness of the rainy season risk is growing, the stereotypical image of heatstroke hasn't caught up with the reality of indoor or humidity-based risks.

**Analysis of TOPIC 2:** While hydration is the top choice for beating the heat (59.3%), the timing is often suboptimal. Most people drink when they feel thirsty, which the Ministry of the Environment warns is a sign that dehydration may have already begun. High humidity prevents sweat from evaporating, causing heat to build up inside the body. Thus, the timing—drinking before thirst—is the most critical factor in rainy season prevention.