If you don’t want to listen to the whole interview, here are some key points from the interview and from Dr. Rhonda Patrick's table of contents page on saunas:

• Important reminders for us survivors of cardiac arrest or those with heart disease: Do not use a sauna when you’ve just had a cardiac arrest or a heart attack. According to Dr. Rhonda Patrick, the sauna is safe to use for the majority of people, even those with heart disease. However, the condition of your heart disease must be stable. If you are unsure of your condition, please talk to your cardiologist before using a sauna.
• Cardiovascular health: Like exercise, long-term sauna use generally improves blood pressure, endothelial function, and left ventricular function, and reduces inflammation.
• Hypertension: Men who used the sauna for two to three sessions every week were found to have a 24% lower risk of developing hypertension, and men who used the sauna four to seven times per week had a 46% lower risk for hypertension, compared to men who used the sauna only once per week. Just a single sauna session has been shown to lower blood pressure and improve arterial compliance.
• The more the better: A large prospective study conducted in eastern Finland has shown that, compared to men who only used the sauna once per week, moderate sauna users (2-3 times per week) are 22% less likely to experience sudden cardiac death, and frequent users (4-7 times per week) are 63% less likely to experience sudden cardiac death. In addition, frequent sauna users were found to be 37% less likely to die from all causes of premature death, regardless of age, activity levels, and lifestyle factors.
• Best way to use a sauna: It is best to use the sauna for 20 minutes at 170 Fahrenheit (76 Celsius, so I guess anything between 75 and 80 will be good) and 20% humidity.