High blood pressure (Hypertension)

Obesity is a medical condition characterized by excess fat in the body. Obesity is measured in terms of body mass index (BMI), which is an estimate of body fat based on weight and height. If BMI is 18.5-24.9 kg /m⊃2;, it is considered normal. If BMI is 25.0-29.9 kg /m⊃2;, it is over-weight and BMI ≥30 kg /m⊃2; it is considered obesity.

Hypertension (high blood pressure) is a common condition, in which the force of the blood pushing against the walls of the arteries (blood vessels) is too high.

The JNC (Joint National Committee) 7 Report classifies blood pressure as:

• ormal blood pressure: Systolic pressure is equal to or less than 120 mmHg and diastolic pressure is equal to or less than 80 mmHg.
• Pre-hypertension: Systolic pressure is 120-139 mmHg or diastolic pressure is 80-89 mmHg.
• Hypertension:
  • Stage 1: Systolic pressure is 140-159 mmHg or diastolic pressure is 90-99 mmHg.
  • Stage 2: Systolic pressure is greater than or equal to 160 mmHg or diastolic pressure is greater than or equal 100 mmHg.

Obesity and health

Excess fat in the body interferes with the functioning of several organs and can lead to certain health conditions, such as:

• High blood pressure
• Heart disease
• Type-2 diabetes
• Sleep apnea
• Fatty liver disease
• Depression
• Correlation of obesity and hypertension

People with obesity have high amounts of fat, which gets deposited on the inner walls of the arteries. This causes the narrowing of the passage of arteries and reducing the blood flow. Hence, the heart pumps harder to supply blood to different parts of the body, thereby increasing the blood pressure.

Obesity occurs when the calorie intake is more than the calories burnt. It can occur due to genetic, behavioral, metabolic and hormonal influences on the body. The quantity of fat in the diet has a greater impact on weight gain when compared to calories alone. These fat calories are stored directly in the fat cells resulting in the weight gain, whereas carbohydrates, such as cereals, bread, fruits, vegetables, and proteins are converted to energy immediately after consumption.

The mechanism of obesity-related hypertension includes

Activation of the sympathetic nervous system (SNS)intake increases the levels of norepinephrine (a chemical present in the body). An increased level of norepinephrine narrows the blood vessel and increases the pressure of blood on the arterial wall. Thus, resulting in hypertension. 

The renin-angiotensin system

system (RAS) is a hormone system that regulates blood pressure and fluid balance in the body. The effects of RAS in the body include higher blood volume, blood pressure, and sodium content. Angiotensinogen, which is derived from the fat cells is the primary driving component of RAS. Due to the excess production of angiotensinogen in obesity, the effects of RAS also increases including high blood pressure.

The amount of intra-abdominal and intra-vascular fat

abdominal fat has the greatest influence in developing hypertension. The excess abdominal fat will produce angiotensinogen, which involves the process of the renin-angiotensin system and increases the blood pressure. Intra-vascular fat is the fat deposition in the walls of the arteries. This fat deposition causes the blood vessels to become narrow, which makes the heart to pump harder and so the pressure of blood flow increases in the blood vessels.

vascular fat may sometimes completely block the blood vessel leading to the development of heart diseases.

High sodium levels in the blood due to increase in renal (kidney) reabsorption

Excess fat in the body interferes with the kidney function and causes sodium reabsorption. This reabsorption holds back a lot of fluid in the body and increases the blood volume. Due to the high blood volume, the force of blood in the blood vessel is increased.

Treatment of obesity-induced hypertension

Blood pressure-lowering medicines, such as RAS blockers (ramipril, losartan, etc), β-blockers (metoprolol, atenolol, etc), and diuretics (hydrochlorothiazide, chlorthalidone, etc) would be prescribed. In some cases, individuals taking these medicines may experience cough, diarrhea, dizziness, and light-headedness.

Medication alone will not be able to fix hypertension in the obese patient. In such patients, medications are always combined with lifestyle modification, such as:

• Maintain calorie intake of 500–1,500 for men or 500–1,200 calories for women
• Maintain a healthy body weight
• Restrict or limit the intake of salt
• Avoid high saturated fats
• Drink plenty of water
• Include fresh fruits and vegetable in the daily diet
• Exercise regularly for at least 30 minutes
• Have adequate sleep

Following these lifestyle changes regularly improves muscle strength and reduces the amount of fat in the body. Thus, it helps in managing hypertension in obese individuals.

Outlook

Obesity and hypertension are common medical conditions seen in people. The presence of these two conditions can cause several health problems, such as heart diseases and kidney diseases. So, managing healthy body weight and taking the prescribed medicines regularly are the best options for reducing hypertension in obese patients.