Medicinal Marvels of Walking: Preventing and Managing Chronic Diseases
3. Metabolic Health: Walking off Sweetness Overload
After a nice dinner, it feels normal to relax on the couch or sit at the computer. But besides the pile of dirty dishes, the sugar overload in our blood also needs clearing. A short walk after the meal may just do the trick. Over time, uncontrolled high blood sugar can lead to type 2 diabetes, which in turn is also a risk factor for other diseases down the road, such as cardiovascular disease, kidney disease and even dementia.
What is metabolic health?
Metabolic health refers to how well the body processes, uses and stores energy from the food we eat. Metabolic dysfunction tends to lie at the root of most chronic diseases. The glucose from carbohydrate-rich foods entering the blood vessels starts to overflow if there is no adequate clearance system. It reminds me of the junk piling up in the beautiful rainforest of Papua New Guinea as a side effect of modernisation with no waste removal system, that I described in part 1 of this series.
Glucose overflow
After dinner
If the hours following dinner are sedentary, where does the glucose broken down from the carbohydrates go? Without getting too bogged down by biochemical terms, here is an attempted explanation of the general chain of events (Graphic 2). The glucose enters our blood and the pancreas releases the hormone insulin to open cellular doors, proteins called GLUT4 transporters inside muscles and fats. In response to this insulin, glucose flows through these doors into the muscle cells for storage as glycogen. Glucose is also absorbed by the liver without the need for insulin via its GLUT2 transporters. Insulin is needed by the liver to store the absorbed glucose and it suppresses the release of fat, so that the body prioritises glucose for energy. Glucose also flows passively into the brain and red blood cells through GLUT1 and GLUT3 transporters, without the need for insulin to open these doors. For more details, see Richter et al.’s ‘A comprehensive view of muscle glucose uptake’ (2025).
After ongoing sedentary periods (with insufficient muscle contraction)
Over weeks, months and years, the excess glucose is turned into fat and stored in places it does not belong, e.g. muscles, liver and pancreas (ectopic fat). This fat interferes with normal insulin action. Muscle and fat cells lock their doors to prevent the entry of glucose, a state called insulin resistance. The liver ‘thinks’ the body needs more fuel and keeps releasing glucose. The pancreas keeps producing more and more insulin, until its β-cells become overworked and can eventually die.
The cells that cannot lock their doors to glucose, such as those lining blood vessels and those in nerves, kidneys and eyes, become overwhelmed. The machines in each cell that convert glucose into energy, called mitochondria, become jammed (see Brownlee’s Unifying Mechanism). They leak reactive molecules that damage the cell, causing inflammation, scarring and rigid blood vessels. The smallest blood vessels in the eyes and kidneys and the nerves in hands and feet are affected first (Graphic 3).
Too much glucose damages tissues directly by binding to proteins such as collagen and elastin making skin and blood vessels rigid. It can also weaken the ability of white blood cells to find and engulf pathogens, leading to longer-healing wounds and more frequent infections. Ongoing stiffened blood vessels and chronic inflammation are routes by which diabetes increases the risk of chronic kidney disease, heart disease and dementia.
Diabetes epidemiology
Currently approx. 589 million adults (11.1% of the adult population globally) have diabetes (90–95% is type 2 diabetes) and at least 635 million more have prediabetes, measured as Impaired Glucose Tolerance (IDF Diabetes Atlas 11th edition 2025). These numbers are expected to rise over the next decades, e.g. 853 million (approx. 13.0% of adults globally) in 2050. Over USD 1 trillion was spent on diabetes in 2024. This represented 12% of global health expenditure. The good news is that type 2 diabetes is largely preventable and in its earlier stages reversible.
Opening more glucose doors by walking
The previous paragraphs contain a pretty grim picture of what happens in our bodies after prolonged periods of high glucose levels and insulin resistance. One relatively easy remedy to halt glucose overload and prevent the detrimental consequences to our health is to go for simple daily walks.
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Our muscles upon contracting, not only open doorways to absorb glucose with the help of insulin, but also open up doorways independent of insulin. Muscle contraction activates the enzyme AMPK (AMP-activated protein kinase), an energy sensor in our muscle cells (Graphic 4). This activation leads to more GLUT4 transporters in muscle cells moving to the surface of the cells to absorb glucose from our bloodstream more quickly. Regular walking also causes more GLUT4 transporters to be manufactured in muscle cells. This absorption of glucose requires no insulin, so people who already have insulin resistance can clear the excess glucose out of their blood by contracting their skeletal muscles, or going for a walk. For more details, see the reviews Exercise, GLUT4, and skeletal muscle glucose uptake (2013) and Skeletal muscle energy metabolism during exercise (2020).
Beyond insulin: balancing other hormones
Walking also helps to diminish fat, by using it for energy. During extended walks or walks before meals, the hypothalamus in the brain signals the adrenal glands to release adrenaline, triggering stored fats to break down into fatty acids which then enter the blood stream to be used for energy by muscles. Visceral fat is broken down first as it has more adrenaline receptors than fat stored under the skin. Visceral fat is the more dangerous type of fat which is stored around internal organs in the abdominal cavity. By reducing this fat, we suppress inflammatory proteins like TNF (Tumor Necrosis Factor)-α, which can otherwise impair our insulin receptors.
Walking also regulates the hormones leptin (signalling fullness; by reducing visceral fat, walking reduces leptin resistance), adiponectin (which is increased by walking, leading to improved insulin sensitivity, reduced vascular inflammation and less damage to blood vessels) and cortisol (walking provides a physical outlet for the stress hormone cortisol, while signalling the HPA (Hypothalamic-Pituitary-Adrenal) axis to keep chronic inflammation in check). For more details, see these reviews on the hormonal breakdown of fats and the anti-inflammatory effects of exercise.
Step count: how many, how fast and when
So how many steps are actually needed to address this glucose overload? The number of steps needed is not exact, of course, and should only be treated as indicative. The general pattern we see is that the more steps we take, the lower the association with developing type 2 diabetes. In a meta-analysis (2025) (57 studies, 35 cohorts) 6000, 9000, and 12000 steps were associated with a 12%, 19% and 27% lower risk, respectively, of developing type 2 diabetes when compared to taking 2000 steps per day. This prospective cohort study following 6,042 participants wearing step tracking devices for a median of four years found that participants taking about 9,000 steps per day had a 44% lower risk of developing type 2 diabetes, when compared to those taking 6,000 steps per day.
Older adults may need fewer steps to achieve greater risk reductions for type 2 diabetes. This prospective study from 2020 found that in a group of 70 year olds, a daily step count of at least 4500 was associated with a 59% lower risk of developing diabetes than a lower step count. The risk decreased sharply until about 6000 steps per day and leveled off at around 8000 steps. Reducing visceral fat was found to account for a large part of these associations.
Speed and Cadence
Walking speed reduces the risk of developing type 2 diabetes even more. This systematic review and meta-analysis (2024) found that compared to an easy, slow pace of under 3.2 km per hour, an average pace (3.2 to 4.8 km per hour (2–3 mph)), a fairly brisk pace (4.8 to 6.4 km per hour (3–4 mph)) and a very brisk pace (more than 6.4 km per hour(>4mph)) were associated with a 15%, 24% and 39% lower risk of type 2 diabetes. When the researchers also looked at studies adjusting for walking duration and step count, these risk reductions still held. This means that walking faster is associated with these risk reductions when comparing people who walk for the same amount of time or steps. The practical message therefore seems to be: walk faster if you can, especially if you don’t have time for a longer walk.
Cadence (steps per minute) may be easier to measure when it come to walking faster. Although individual cadence can vary based on height and leg length, this is a rough conversion of steps per minute based on this laboratory-based study: average pace = 85–110 steps per minute, fairly brisk pace = 110–130 steps per minute and very brisk = at least 130 steps per minute.
Timing
As glucose peaks occur after meals, when we walk is just as important for reducing the damage from too much glucose in our bloodstream, than how many steps we take. Although average lower glucose levels are better for metabolic health in general, the first hour following a meal when glucose levels are peaking is especially important. This International Diabetes Federation position paper from 2024 reviewed studies showing that glucose levels at one hour after consuming a standard sugary drink (the 75 g oral glucose test) were more predictive of type 2 diabetes and cardiovascular disease than the standard 2-hour test. This emphasizes the importance of blunting the initial glucose peak after carbohydrate consumption. The authors of this systematic review and meta-analysis (2023) conclude that walking or other types of physical activity are the most effective for lowering the surge of glucose in the blood when carried out within 30 minutes of a meal compared to no physical activity or physical activity carried out before a meal. This experimental study from 2025 showed that walking for 10 minutes straight after a meal is more effective for lowering peak glucose levels than not walking or going for a walk 30 minutes after a meal. When it comes to managing type 2 diabetes, this study from 2016 concluded that walking for 10 minutes after three meals was more effective than walking for 30 minutes at any time of the day.
The next article will cover the walking mechanisms impacting heart and vascular health, much of which is downstream from metabolic health. There I focus on the role of walking in helping to prevent and manage one of the most prevailing risk factors for various chronic diseases: high blood pressure. I will also examine the ensuing chronic diseases, such as stroke and heart disease and the number of steps which are considered beneficial to prevent and manage these diseases.
