Cardiologists suggest that extreme heat can take a toll on one’s heart. People with cardiovascular issues are more prone to health issues due to dehydration and salt loss. Dr. Prabhakar C Koregol, Consultant - Cardiac Sciences & Interventional Cardiology, Fortis Hospitals stated that the increased heat, low-sodium diet, excessive alcohol consumption, poor blood circulation, and the use of sedatives and diuretics with hypertension meds can impact the heart functions.

Dr. Koregol explained that during summers, heat, and humidity cause an increased flow of blood to the skin. Hence, the heart works at an increased rate causing an increase in blood circulation. Along with constant sweating, the fluid content in the body is reduced causing dehydration and straining the heart. In this chain reaction, adding blood pressure medicines that give an opposite effect is the major risk factor for people with pre-existing cardio conditions. 

He suggested simple practices for the heart patients such as avoiding strenuous activity, avoiding caffeine or alcohol, regular checking of BP, checking sodium-potassium levels in the blood, and regular intake of medication to maintain a healthy heart during the intense heat.

(Source: https://www.hindustantimes.com/lifestyle/health/cardiologist-on-important-lifestyle-changes-for-heart-patients-during-summer-season-101651296678601.html )