 According to the Department of Health and Human Services, extreme heat can trigger asthma and chronic obstructive pulmonary disease. Dehydration can lead to kidney injury and blood pressure problems. Blazing heat can also pose risks for people struggling with mental health issues and can worsen acute psychiatric and substance use symptoms. Kelly Visrell with Children's Defense Fund Ohio says water safety and drowning remains a top risk for people participating in water activities, such as swimming or boating.