Fasting is abstinence from food for a minimum of eight (8) hours. This abstinence can be
for religious reasons (the month of Ramadan, Lent season), cosmetic or health choices.
Fasting is a state of reduced nutritional intake. In healthy subjects, fasting initially causes
the release of glucose from liver glycogenolysis in the early hours, followed by glucose
release in the later part of the fasting period by gluconeogenesis from the kidney, muscle,
and liver to maintain normal glucose homeostasis and energy.
With prolonged fasting, fatty acid mobilisation from adipose tissue provides fuel and leads
to the formation of ketone bodies. This may result in weight loss.
In subjects with diabetes, prolonged fasting leads to an exaggerated fasting glucose
homeostatic response, mediated by increased glucagon levels and low insulin secretion,
which results in excessive glycogen breakdown and increased gluconeogenesis.

Cardiovascular Benefits of Fasting

1. Improves Key Risk Factors for Heart Disease
   This is the most well-documented area. Fasting can lead to significant improvements in
   several biomarkers that are directly linked to cardiovascular health.
   Blood Pressure: Numerous studies show that various forms of fasting can lead to a
   reduction in blood pressure. This is partly due to weight loss, but also because fasting can
   improve the flexibility of blood vessels and promote the excretion of sodium, which helps
   lower blood volume and pressure.
   Cholesterol and Triglycerides: Fasting has been shown to improve lipid profiles. Some
   studies, particularly those using alternate-day fasting, show a reduction in LDL (“bad”
   cholesterol) levels. Fasting is very effective at lowering blood triglyceride levels, a major
   risk factor for heart disease and stroke. Reduction of triglyceride levels is one of the most
   consistent benefits of fasting. However, the impact on HDL cholesterol (“good”
   cholesterol) is mixed, with some studies showing it remains stable or even increases
   slightly.
   Blood Sugar and Insulin Sensitivity: Fasting gives the body a break from constantly
   processing glucose. This helps lower fasting insulin levels and reduce insulin resistance.
   When cells are more sensitive to insulin, they can more effectively remove sugar from the2
   bloodstream, leading to more stable blood sugar levels. This is crucial for preventing type 2
   diabetes, a major risk factor for heart disease.
   Inflammation: Chronic inflammation is a key driver of atherosclerosis (plaque buildup in
   arteries). Fasting has been shown to reduce markers of systemic inflammation, such as Creactive protein (CRP).
2. Activates Cellular Repair Processes
   Beyond the risk factors, fasting triggers profound cellular changes that protect the heart
   and blood vessels.
   Autophagy: This is a critical cellular “cleanup” process that ramps up during fasting. It is
   one of the body’s internal housekeeping services. Cells break down and recycle old,
   dysfunctional proteins and damaged components that can contribute to ageing and
   disease, including heart disease. By clearing out this cellular “junk,” autophagy helps keep
   cells, including those of the heart and arteries, healthy and functioning optimally.
   Mitochondrial Health: Mitochondria are the powerhouses of the cell. Fasting can stimulate
   the growth of new mitochondria (mitochondrial biogenesis) and improve the function of
   existing mitochondria. This ensures that the heart muscle, which requires a large amount
   of energy, has a reliable and efficient energy supply.
3. Enhances Stress Resistance
   Mild stress from fasting can actually make the cells stronger, a phenomenon called
   hormesis. Hormesis is a biological phenomenon where low-dose, controlled exposure to a
   stressor (e.g., a toxin, exercise, temperature change, fasting) triggers adaptive, beneficial
   cellular repair that increases organism resilience. Fasting places a low-level, beneficial
   stress on cells. In response, they ramp up production of antioxidants and repair enzymes.
   This builds a stronger defence against the types of oxidative stress and damage that can
   lead to heart disease over time. The temporary stress makes them more resilient in the long
   run, thus boosting health.
4. Promotes Weight Loss and Reduces Visceral Fat
   Obesity is a primary driver of cardiovascular disease. Fasting is an effective weight-loss
   strategy for many people because it naturally reduces calorie intake. Importantly,3
   intermittent fasting has been shown to be particularly effective at reducing visceral fat—the
   deep belly fat that surrounds organs and is strongly linked to inflammation, insulin
   resistance, and heart disease.
   

Health Risks associated with Fasting

Although fasting has been shown to confer health benefits, there are documented
complications associated with fasting.

Hypoglycemia
Prolonged undernutrition depletes the body’s glycogen stores. This, together with
increased use of the body’s fat stores for energy production, increases the risk of low blood
glucose levels (hypoglycaemia). Hypoglycaemia poses risks to the brain and the heart. In
the brain, it affects neuronal function, and this malfunction can present as loss of attention
and concentration, confusion, convulsions and loss of consciousness. Hypoglycaemia
increases the risk of cardiac events such as arrhythmias and myocardial infarction (heart
attack).

Hyperglycemia
This is common in people with disorders of glucose metabolism (diabetes). Elevated
glucagon and reduced insulin levels increase gluconeogenesis (glucose production). This
is exacerbated by the dehydration often associated with fasting. Hyperglycemia confers
cardiovascular risk.

Dehydration

Fasting reduces the amount of water absorbed from the food we eat. This increases the risk
of dehydration, which can lead to complications such as hypotension (low blood pressure),
ischemic encephalopathy (brain injury), and kidney injury.

Thrombosis
Fasting can lead to dehydration and hyperglycemia. These clinical states can contribute to
the formation of blood clots (thrombosis) at different sites in the body (Virchow’s triad).

Thrombosis in vital organs (heart, brain, kidney) can be life-threatening.

Precautions to take during Fasting
While the benefits are significant, it’s crucial to approach fasting safely and to be aware of
the potential downsides:

Consult Your Doctor First: This is the most important step. Fasting is not suitable for
everyone. A pre-fasting medical assessment would help determine the degree of risk
associated with fasting for that particular individual, given their background health
condition.

People living with hypertension and/or diabetes should adhere to their medications to
maintain normal levels of blood pressure and blood glucose throughout the fasting period.
Dosages may need to be adjusted to prevent dangerous drops in blood sugar or blood
pressure.

Hydration and Nutrition: It is vital to stay well hydrated with water during fasting periods, as
this prevents dehydration, hyperglycaemia and thrombosis.
In conclusion, fasting offers a multi-faceted approach to improving cardiovascular health.
It not only improves traditional risk factors such as blood pressure, cholesterol, and blood
sugar but also activates powerful cellular repair mechanisms that can protect the heart
and blood vessels from the ground up.