4. Objectives
Effect of heat on cardiovascular system
Dehydration and how it affects heart and
circulation.
Precautions and prevention
5.
6. Effect of heat
• Dehydration
• Direct damage of cells of heart muscles and
blood vessels.
7. Water Loss
• Insensible loss (evaporation) – 500 ml /d
• Sweat : 100 to 8000 ml / d
The solute loss can be as much as
350 mmol/day of sodium under the most
extreme conditions
• Urine output – 1500 ml/d
Total water loss : 2500 ml/d (average)
12. What is the normal requirement
of water intake ?
• A – 1 Liter per day
• B – 1.5 Liters per day
• C- 2 Liters per day
• D – 3 Liters per day
13. Water requirement
• Water in your body makes up about 60
percent of your body weight. Every system in
your body depends on water.
• Men : 3 liters (12 glasses)
• Women : 2.2 liters (9 glasses).
14. How Heat Affects Blood Pressure
• Heat causes loss of fluid and dehydration.
• Loss of fluid leads to me low intravascular
volume and cardiac output.
• The above eventually lead to low blood
pressure.
15. • Blood pressure will increase after exposure to
cold temperatures and decrease after a time
of exposure to hot temperatures.
• Van Voorhees, Benjamin W. “Blood Pressure.” Medline Plus.
21 Jul 2006. U.S. National Institute of Medicine and the
National Institutes of Health. 10 Nov 2007
16. Summer Heat Can Affect Blood
Pressure
• The American Heart Association recently
published the results of a European study
regarding hot weather and blood pressure.
• Hot weather may affect a drop in blood
pressure during the day - and an increase at
night.
• CHECKING BLOOD PRESSURE DAILY CAN HELP
AVERT PROBLEMS.
17. Cardiac Drugs and Heat
• Diuretics cause fluid loss through excessive
urination and precipitate dehydration.
• Certain blood pressure tablets like calcium
channel blockers and ACE Inhibitors cause
further dilatation of blood vessels causing
more significant fall in blood pressure.
18. Effect of heat on heart and blood
vessels
• High temperatures increase heat stress in the
heart and the blood vessels.
• The stress lead to inflammation and cell injury
of heart and vessel muscles.
• These responses increase the chances of heart
attack and heart failure .
19. Symptoms: General
feeling of tiredness or
fatigue.
First Aid: Fluid
replacement and rest.
Transient Heat Fatigue:
20. Symptoms of heat exhaustion
• headaches
• heavy sweating
• dizziness or fainting (syncope)
• a weak and rapid pulse
• muscle cramps
• nausea, vomiting or both
21. Symptoms of heat stroke:
• warm, dry skin with no sweating
• strong and rapid pulse
• confusion and/or unconsciousness
• high fever
• throbbing headaches
• nausea, vomiting or both
22. Symptoms: Syncope means
“fainting.” First signs are
dizziness, feeling light-headed
and perhaps nauseous, then the
person may faint. Usually occurs
in the beginning of heat stress
season before the circulation
system is adapted.
First Aid: Lay victim in a cool
location horizontally with feet
elevated. If conscious, give fluids.
Treatment the same as shock.
Heat Syncope
(fainting)
23. Predisposing
Factors:
very small body size
overweight
over 40 years old (the older
the more sensitive)
previous heat illness
heart disease
high blood pressure
diabetes
inactivity
physical activity
25. Prevention and precautions
• Wear light and comfortable clothing and foot
wear.
• Stay in cool environment.
• Use cooling fans or air conditioners.
• Avoid excessive activity that increases heat
production, sweating and dehydration.
• Drink plenty of fluids (water) regularly.
• Add pinch of salt if you sweat excessively.
26. What to drink ?
• Electrolyte drinks (e.g. Gatorade) are usually not
needed.
• Stay away from caffeinated carbonated, diet drinks
and alcohol as they take water out of your body.
• Water is the best; juices and/or non caffeine sport
drinks are also good (juices contain energy restoring
glucose).
28. Remember, when it’s hot:
Heed your body! watch for symptoms!
Ensure you’re drinking enough!
Adjust your activity level – slow down!
Take clothing/PPE into account!
Acclimatization does not decrease your body’s need for water! You must continue to take scheduled water breaks to replace the fluids your body has lost through sweating. Also, remember that acclimatization is lost after 7 to 10 days away from the job, in periods of cool weather or by working in air–conditioning.