Introduction 

Obesity is a complex disease influenced by a variety of biological, psychological, socioeconomic, and environmental factors, and has emerged as a global health concern with profound consequences for cardiovascular health. Obesity is defined by the World Health Organisation as having a body mass index (BMI) of 30 kg/m² or higher, whereas being overweight is defined as having a BMI of 25-30 kg/m². While BMI is widely used, its limits in accurately measuring the body fat content of people are restricted, particularly when considering variances by gender, age, race, and ethnicity.¹

The intensity of the obesity pandemic is shown by astonishing numbers, with the Global Burden of Disease (GBD). Alarmingly, about half of the global population is overweight or obese, which has serious consequences for public health. Obesity has a significant impact on the global burden of cardiovascular disease (CVD), with high BMI being linked to more than two-thirds of CVD-related fatalities. Notably, racial and ethnic differences continue, with certain demographic groups experiencing disproportionately high rates. These discrepancies are preserved by complex interactions of racial and ethnic discrimination, weight stigmatisation, and structural imbalances, which increase the risk of CVD among marginalised people.¹

The consequences are not just limited to those beyond the age of maturity, with adolescent obesity emerging as a major health issue worldwide. The increase in obesity among teenagers over the last few decades signals a potential future CVD burden, needing immediate intervention to stem the tide of obesity-related cardiovascular morbidity and mortality. This article delves into the complex interplay between these two major health concerns, focusing on the mechanisms behind how obesity leads to CVD and effective prevention strategies.

How does obesity lead to heart disease? 

Obesity can increase the risk of heart disease in a variety of ways, including high cholesterol and blood sugar, belly fat, problems with small blood vessels and hardened arteries, issues with the lining of blood vessels, and heart rhythm problems. 

• High cholesterol and Blood sugar: People living with obesity frequently struggle to digest fats and sugars. This can cause dyslipidemia, which is characterised by an excess of certain fats in the blood (such as triglycerides) and an insufficient amount of “good” cholesterol, known as HDL-C.² Additionally, the body can develop resistance to insulin, a hormone that aids in blood sugar regulation. This resistance makes it difficult for cells to use sugar properly and can exacerbate dyslipidemia, which can lead to complications such as clogged arteries and cardiovascular disease³
• Belly fat and Problems with metabolism: Abdominal obesity, or excess belly fat, is a major risk factor for heart disease. This type of fat produces molecules that induce inflammation making it difficult for the body to use insulin, resulting in blood sugar issues. Abdominal obesity is also associated with additional issues such as high blood pressure and abnormal blood fats, both of which can damage blood vessels and raise the risk of heart disease⁴
• Problems with small blood vessels and Hardened arteries: Obesity can also cause problems with the small blood vessels in the heart, making it difficult for them to open and allow blood to pass through. Obesity generates inflammation and stress in the blood vessels, reducing their flexibility. Over time, this can lead to atherosclerosis, a condition in which fatty deposits accumulate in the arteries, hardening and narrowing them. This can reduce blood supply to the heart, resulting in chest discomfort or possibly a heart attack⁵
• Problems with the Lining of Blood Vessels: The endothelium (the innermost lining of a blood vessel) is essential for maintaining blood vessel health. Obesity can promote inflammation in the endothelium, causing it to function less effectively. This can result in reduced blood flow and an increased risk of blood clots, both of which can cause heart attacks and strokes⁶
• Heart rhythm problems and Fat around the heart: Obesity can also interfere with how the heart beats by disrupting the balance of substances that regulate it, resulting in irregular heart rhythms or arrhythmias. Furthermore, fat around the heart, known as epicardial adipose tissue, can release chemicals that induce inflammation and damage the heart muscle, increasing the risk of cardiac rhythm issues⁷

Moving beyond the complex ways in which obesity affects cardiovascular health to the world of symptomatology and diagnosis, it is critical to identify the manifestations and clinical signs that signal the development of cardiovascular issues in people living with obesity for timely intervention and specialised therapy.

Symptoms and diagnosis of obesity 

Obesity hypoventilation syndrome (OHS) is characterised by inadequate breathing during sleep, which results in reduced oxygen and increased carbon dioxide in the blood. Understanding its symptoms is essential for early detection and intervention. 

Common signs and symptoms of OHS include:⁸

• Breathlessness: Individuals with OHS often experience shortness of breath, especially during physical exertion or lying down
• Daytime Sluggishness or Sleepiness: Excessive daytime sleepiness is a hallmark symptom of OHS, often accompanied by feelings of lethargy and fatigue. This may significantly impact daily functioning and quality of life
• Dizziness: Dizziness or lightheadedness may occur due to inadequate oxygen levels in the blood, which can lead to impaired circulation and balance
• Fatigue: Chronic fatigue or extreme tiredness is a common complaint among individuals with OHS, affecting their ability to engage in daily activities and tasks
• Headaches: Persistent headaches may arise due to inadequate oxygenation and impaired respiratory function associated with OHS
• Respiratory Symptoms: Individuals with OHS may exhibit respiratory disturbances during sleep, such as loud snoring, choking, gasping for air, or experiencing difficulty breathing. These symptoms often worsen over time and may be observed by a partner or family member

Diagnosing OHS typically involves a comprehensive assessment by a healthcare provider, incorporating various clinical evaluations and diagnostic tests. The diagnostic process may include the following steps:⁸

• Physical examination: A thorough physical examination allows healthcare providers to assess signs of obesity and respiratory dysfunction, such as increased neck circumference, elevated blood pressure, and signs of respiratory distress
• Measurement of weight, height, and BMI: Accurate measurement of weight, height, and calculation of BMI are essential components of the diagnostic evaluation, providing insight into the severity of obesity and potential associated health risks
• Assessment of waist and Neck circumference: Measuring waist and neck circumference helps evaluate central adiposity, which is strongly associated with an increased risk of OHS and other obesity-related complications
• Pulmonary function tests: Lung function tests, including spirometry and arterial blood gas analysis, may be performed to assess respiratory function, oxygenation levels, and the presence of hypercapnia (elevated carbon dioxide levels)
• Sleep study (polysomnography): A sleep study, or polysomnography, is a diagnostic test used to evaluate sleep patterns, breathing abnormalities, and nocturnal oxygen saturation levels. This test is particularly useful for identifying coexisting sleep disorders such as obstructive sleep apnea (OSA), which frequently occurs in conjunction with OHS
• Laboratory Investigations: Additional laboratory tests, such as a complete blood count (CBC), thyroid function tests, and metabolic panels, may be conducted to assess underlying medical conditions contributing to respiratory dysfunction or exacerbating obesity

How can we fight against obesity? 

Addressing this epidemic requires a comprehensive approach encompassing individual lifestyle modifications, behavioural interventions, medical treatments, and public health initiatives. By implementing evidence-based strategies, individuals can achieve sustainable weight loss and reduce the risk of obesity-related complications. Here, we explore various effective strategies to fight against obesity.

Lifestyle modification 

Lifestyle modification is the cornerstone of obesity management, focusing on adopting healthier dietary habits and increasing physical activity levels. This includes:⁹

• Healthy Diet: Emphasising consuming nutrient-rich foods, such as fruits, vegetables, whole grains, lean proteins, and healthy fats, while limiting intake of processed foods, sugary beverages, and high-calorie snacks
• Physical Activity: Incorporating regular exercise into daily routines, including aerobic activities (such as walking, jogging, swimming, or cycling) and strength training exercises, to promote weight loss, improve cardiovascular health, and enhance overall well-being

Behavioural interventions

Behavioural strategies play a crucial role in long-term weight management. Key interventions include:¹⁰

• Setting realistic goals: Establishing achievable and sustainable weight loss goals, focusing on gradual progress rather than rapid results
• Self-monitoring: Tracking food intake, physical activity, and progress towards weight loss goals through journaling, mobile apps, or wearable devices
• Seeking social support: Engaging with friends, family members, or support groups to receive encouragement, accountability, and motivation throughout the weight loss journey

Bariatric surgery

Bariatric surgery may be recommended for individuals with severe obesity (BMI ≥ 40 kg/m² or BMI ≥ 35 kg/m² with obesity-related comorbidities) who have not achieved significant weight loss through lifestyle interventions. Types of bariatric surgery include gastric bypass, sleeve gastrectomy, and adjustable gastric banding. Research has shown that bariatric surgery not only leads to substantial weight loss but also reduces the risk of obesity-related cardiovascular diseases, such as coronary artery disease.¹¹

Psychological support

Addressing underlying psychological factors contributing to obesity, such as stress, depression, anxiety, and emotional eating, is essential for successful weight management. Counselling, therapy, or support groups can provide individuals with coping strategies, stress management techniques, and behaviour modification skills to overcome psychological barriers to weight loss.¹²

Public health initiatives

At the population level, public health efforts are crucial for preventing and reducing obesity rates. Key initiatives include:

• Promoting access to healthy foods: Increasing the availability and affordability of nutritious foods, such as fruits, vegetables, and whole grains, in communities, schools, workplaces, and food retail environments
• Creating supportive environments for Physical activity: Designing urban spaces, parks, and recreational facilities that encourage physical activity and active transportation options, such as walking and cycling
• Implementing policies to Reduce sugary beverage consumption: Enforcing regulations, such as sugar-sweetened beverage taxes or marketing restrictions, to reduce the consumption of sugary drinks and promote healthier beverage choices

Summary

In conclusion, obesity poses a significant risk factor for the development of cardiovascular diseases, with various mechanisms contributing to this association. From dyslipidemia and insulin resistance to inflammation and endothelial dysfunction, obesity exerts detrimental effects on the cardiovascular system, increasing the likelihood of conditions such as coronary artery disease, heart attacks, and strokes. Understanding the manifestations and clinical signs of cardiovascular issues in obese individuals is crucial for early detection and intervention, particularly with conditions like obesity hypoventilation syndrome. Implementing strategies to combat obesity ranging from lifestyle modifications and behavioural interventions to medical treatments and public health initiatives is essential. By promoting healthy diets, regular physical activity, and supportive environments, along with policies to reduce the consumption of unhealthy foods, we can collectively work towards reducing the burden of obesity-related cardiovascular diseases and improving overall public health outcomes.