Have you ever scoffed at the phrase “fit and fat”? What do you know about the obesity paradox? You are probably familiar with obesity’s link to cardiovascular death (CVD), diabetes, hypertension (HTN), stroke and some forms of cancer. However, obesity and CVD association is more complicated than most wellness professionals understand. Wellness professionals could be providing inaccurate information about the devastating effects of being obese.
Obesity is generally calculated using the class model:
18.5 – 24.9
25 – 29.9
30.0 – 34.9
35.0 – 39.9
The risk factors for being overweight or obese have not changed, but how we treat and interact with people around the disease should. Excess weight can lead to coronary heart disease (CHD) and sudden cardiac death (SCD) due to hardening of the arteries, increases in blood pressure (BP), lipids and insulin resistance.
High Blood Pressure and Cardiovascular Disease
Obesity increases blood volume, stroke volume, and cardiac output, leading to an increase in cardiac work. The added workload on the heart can lead to left ventricular dilation and left ventricle hypertrophy, causing high blood pressure (HBP).
However, the link between obesity and SCD is now debatable. The association between SCD and BMI is greatest in middle-aged adults males versus older (>65) adults males. Ironically, weight loss does not reduce the risk of SCD for these individuals.
Overweight and obese patients with HTN have better outcomes than do leaner patients with HTN. Overweight and obese patients with CHD have a lower risk of CVD compared with both underweight and normal weight CHD patients. However, class II obese patients experience increased CV mortality but not total mortality rates. Patients with the best survival rate of a CV episode are overweight and class I BMI. The highest mortality rates are those with class III BMI.
Obesity Paradox is described as patients with acute myocardial infarction (AMI), whereby obese and overweight patients have a lower risk of short-term mortality after AMI than normal weight patients. Paradoxically, resulting in a moderate increase in life expectancy relative to normal weight patients.
Morbid obesity is associated with a small decrease in life expectancy for younger patients but an increase in life expectancy for patients 75 years and older. Ironically, weight loss for patients after suffering AMI is not recommended, because this will likely lead to increasing fat mass and reduce the patient’s survival outcome.
Low body fat and low BMI are independent predictors of higher mortality rates. Those with both low body fat and BMI suffer four times greater mortality rates. Lower body fat and low muscle mass are associated with the worst survival rates when compared to those with higher body fat and higher muscle mass (best survival rates). Obesity paradox is confined to those who are overweight or mildly obese (class I). Those who are extremely obese have the worst CVD prognosis.
Unexamined comorbidity might explain obesity paradox like smoking or an undiagnosed systemic condition in normal weight CHD patients. The signs of CHD are diagnosed earlier for obese patients, increasing their survival outcomes. Contrasted with obese patients who have comorbidities may die before developing severe CHD. Early diagnosis of CHD creates a disproportionately higher survival rate versus normal weight patients.
The female heart depends on fatty acids for energy, whereas men’s do not. Survival rates are higher for women even with higher body fat levels. Additionally, women use of fats and sugars for energy does not seem to have the same heart clogging effect that men experience, which is thought to be a benefit of estrogen.
BMI is a useful calculation for large population studies, but can lead to misdiagnosis for individual patients. Abdominal obesity is linked to SCD, but waist to hip ratio predicts SCD. Visceral fat mass increases the risk of hardening of the arteries. Hardening of the arteries is a major cause of HBP. Abdominal and visceral fat mass affect young and old regardless of BMI. Abdominal fat is an independent risk factor for CHD.
It is possible non obese people acquire CHD in different ways than obese people; researchers may need to study the two populations as two separate distinct populations.
Cardiovascular Fitness and Cardiovascular Disease
Obesity paradox explained through cardiovascular fitness (CVF). Patients with high abdominal fat with CHD who have a moderate level of CVF had a lower risk of CVD. Obese patients who have a high CRF had lower mortality rates than did patients without CHD and lower CVF. For every 1 MET increase in CVF patients experienced a 15% decrease in all CHD episodes.
Individuals with lower CVF have a twofold higher risk of all mortalities regardless of BMI. Overweight or obese people with CVF have similar mortality as normal weight individuals. Cardiovascular fitness is a much better predictor of all major health outcomes.
Patients with CHD who lose weight without strength training and aerobic exercise experience a 60% increase risk of CVD. Weight loss without exercise can reduce muscle mass, muscular strength decreases CVD risk factors and lowers mortality rates. Patients with CHD who exercise to lose weight reduce all mortality risk factors by 15%.
The phrase “fat and fit” was debatable for many years, research shows that there is no longer a debate. Physical activity needs to replace weight loss instructions for overweight and obese individuals. Specifically, strength training and aerobic exercise are the most important treatments for CHD, HTN, diabetes and strokes..
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