Heart Patients Beware Of Summer Beat the Heat 

by Dr Harinder  Singh  Bedi 
High environmental temperatures and humidity  are uncomfortable for most of us, but for those with heart disease ,  they can be deadly. Our Circulatory system plays a crucial role in dissipating heat from the body esp in summers . The heart responds to a rise in temperature by a faster pumping. Simultaneously blood vessels of the skin dilate, facilitating the flow of warm blood from internal organs to the body surface, observed as a flushed face on a hot day. This favors  heat loss . Moderate exercise may result in up to tenfold increase in heat production with a resultant rise in heart rate .  Strenuous physical effort in hot and humid weather may be particularly deleterious in heart disease as it  lowers the threshold for a heart attack .

When the pumping action of the heart is severely  compromised as in heart failure blood flow through internal organs like liver and kidney becomes sluggish. This may impair the functioning of these organs. Diversion of blood flow to the skin during exercise in hot weather further reduces blood flow to these organs. This problem may be aggravated by sweating induced dehydration and decrease in blood volume. 

Possible Consequences of Hot/Humid Weather in a Heart Disease patient
   
•    Low threshold for heart attack 
•    Aggravation of heart failure
•    Heart rhythm disorders ( arrhythmias)
•    Liver dysfuntion
•    Kidney dysfunction

Medications taken by many patients with heart disease can also cause problems in extreme heat.  During hot weather, diuretics (water pills to reduce fluid retention in patients with heart failure and high blood pressure )  may actually cause dehydration and a thicker blood . However, heart failure patients should be warned against drinking  large amounts of fluid - as recommended to the general public during heat spells -  as this could add significant stress on heart . 

Keep Your Cool
Overall, individuals with heart disease should follow the same guidelines as healthy individuals, but with an extra helping of precaution:

-- Stay inside during the hottest part of the day.

-- If your home isn't air conditioned or air cooled , try to find someplace in the house that is the coolest eg the basement.

-- Limit your activity.

-- Wear loose-fitting, light cotton clothing.

-- Stay hydrated and avoid caffeine and alcohol.

-- Have someone check in on you.

Keep Your Heart Cool in the Summer Heat:
The best advice for avoiding heat stress is to keep as cool as possible. Air conditioning can provide lifesaving relief from heat stress, especially if you have heart disease . If you don't have air conditioning, spend as much time as possible in cool shopping malls, senior centers, libraries, movie theaters, or in the coolest room in your home . Indigenous methods like air coolers , khas water chicks etc are also quite effective.
•    Fans and cross ventilation are important  
•    Cool baths or showers provide relief from the heat 
•    Loose fitting, lightweight, light colored cotton clothing is more comfortable in hot weather.  While working in Sydney I noticed the Australian campaign of – Slip-Slop-Slap {Slip on a full sleeved loose shirt, Slop on some sunscreen (to protect from skin cancer) and slap on a hat} – this is a very advice one and esp useful for heart patients too.
•    Your body needs more water in hot weather Don't wait until you are thirsty to have water . If you have heart disease CHECK WITH YOUR DOCTOR for advice on how much water you should drink 
•    Take local seasonal fruits with high water content eg watermelon, cucumber etc 
•    Curtail unnecessary physical activity during extremely hot weather. 
•    Avoid over spiced hot foods and heavy meals  
•    Watch salt use .Check with your doctor before increasing the amount of salt or potassium in your diet.  
•    Avoid alcohol and caffeine . Alcohol acts as a diuretic, resulting in fast water loss .In addition, alcohol can promote a sense of well-being, making you less aware of the danger signs of heat stress 
•    If you live alone, make sure a relative or neighbor checks on you regularly 
Taking the proper precautions during hot weather can significantly reduce a heart patient’s  chances of suffering from heat-related illness this summer.

However summer does not mean the end of your exercise activities. It is best to plan your exercises early in the morning before the day heats up, or in the evening, when things start to cool down. If the weather is too unbearable, though, head indoors. Activities as suggested by the  American Heart Association include going to an air conditioned  gym. You also could start a walking group with your friends at your local AC mall !!! – an extremely entertaining form of exercise – as long as you’re not a compulsive shopper !!! . Take up an indoor sport, like badminton, table tennis or indoor aerobics and yoga . When it's really hot out, swimming  is the best exercise . You can cool off by doing a lot of floating, but to get your heart pumping and to burn some calories , do some laps, or take a water aerobics class. It's a great workout without the strain on your joints. And, you stay cool in the water, so that's a plus.
So – enjoy the summers – but stay cool !

The author is Director  Cardio-Vascular & Thoracic Sciences at the Grecian Park   Hospital in Mohali  and is the Patron and Founder President of the Association of the North Zone Cardio Thoracic & Vascular Surgeons. He was earlier with the Escorts Heart Institute in Delhi and the St Vincents Hospital in Australia.