मेटाबोलिज्म : जिन्दा रहने के लिए जरूरी Metabolism: An Essential Process for Life

Metabolism: An Essential Process for Life 

Author : Dr. P. D.GUPTA

(Former Director Grade Scientist, Centre for Cellular and Molecular Biology, Hyderabad, India)


Simply put, your metabolism is all of the chemical reactions that help keep your body alive. It also determines how many calories you burn per day in your daily activities such as while resting, exercising and other house hold activities.. The faster your metabolism, the more calories you burn. The regulatory factors of metabolism include age, height, muscle mass and hormonal milieu. 

Less Active with Age

Unfortunately, research shows that your metabolism slows down with age; older adults are typically less active and burn fewer calories through activity. A few reasons for this include less activity, muscle loss and the aging of your internal components. Your activity levels can significantly affect the speed of your metabolism. Staying active can help prevent this drop in metabolism.  

One study of 65 healthy young people (21–35 years) and older people (50–72 years) showed that regular endurance exercise prevents metabolism from slowing down with age.

Lose Muscle with Age

The average adult loses 3–8% of muscle during each decade after 30  In fact, research shows that once you reach 80, you have roughly 30% less muscle than when you were 20 which can lead to fractures, weakness and early death. Because muscle mass is affected by your activity level, being less active is one reason why you lose more muscle with age.

Other reasons include consuming fewer calories and protein, as well as a decrease in the production of hormones, such as estrogen, testosterone and growth hormone.

Metabolic Processes Slow Down with Age

How many calories you burn at rest (RMR) is determined by chemical reactions inside your body. Two cellular components that drive these reactions are your sodium-potassium pumps and mitochondria The sodium-potassium pumps help generate nerve impulses and muscle and heart contractions, while the mitochondria create energy for your cells.

Research shows that both components lose efficiency with age and thus slow down your metabolism.

For instance, one study compared the rate of the sodium-potassium pumps between 27 younger men and 25 older men. The pumps were 18% slower in older adults, resulting in burning 101 fewer calories per day.Another study compared changes in the mitochondria between 9 younger adults (average age of 39) and 40 older adults (average age 69). Scientists found that older adults had 20% fewer mitochondria. Additionally, their mitochondria were nearly 50% less efficient at using oxygen to create energy — a process that helps drive your metabolism.

That said, compared to both activity and muscle mass, these internal components have a lower effect on the speed of your metabolism.

Metabolism Slow Down with Age 

The speed of your metabolism is affected by your activity levels, muscle mass and several other factors. As a result, metabolic speed varies from person to person.

For instance, one study compared the RMR of three groups of people: those aged 20–34, 60–74 and over 90. Compared to the youngest group, people aged 60–74 burned roughly 122 fewer calories, while people over 90 burned around 422 fewer calories.

However, after accounting for differences in gender, muscle and fat, scientists found that the people aged 60–74 burned only 24 fewer calories, while those over 90 burned 53 fewer calories on average daily.

This shows that maintaining muscle is incredibly important as you age.

Another study followed 516 older adults (aged 60 plus) for twelve years to see how much their metabolism fell per decade. After accounting for muscle and fat differences, per decade, women burned 20 fewer calories at rest, while men burned 70 fewer calories.

Interestingly, both men and women were also less active and burned 115 fewer calories through activity per decade. This shows that staying active as you age is crucial to maintaining metabolism.

Nevertheless, one study found no difference in RMR between women of all ages. However, the oldest group of people in the study lived very long (over 95 years), and it is thought their higher metabolisms are the reason why.

In short, research seems to show that being less active and losing muscle has the greatest negative effect on your metabolism.

Prevent Slowing Down Metabolism with Age 

Although the metabolism typically slows down with age, there are many ways one prevent it.  This includes resistance training, high-intensity training, getting plenty of rest, eating enough protein and calories and drinking green tea.

1. Try Resistance Training

Resistance training, or weight lifting, is great for preventing a slowing metabolism; It offers the benefits of exercise while preserving muscle mass 

2. Try High-Intensity Interval Training(HIIT)

 It is a training technique that alternates between intense anaerobic exercise with short periods of rest.  It also continues to burn calories long after you finish exercising. This is called the “afterburn effect.” It occurs because your muscles need to use more energy to recover after exercise. In fact, research has shown that HIIT can burn up to 190 calories over 14 hours after exercising. Research also shows that HIIT can help your body build and preserve muscle mass with age.

3. Get Plenty of Sleep

Research shows a lack of sleep can slow down your metabolism. Fortunately, a good night’s rest can reverse this effect. One study found that 4 hours of sleep reduced metabolism by 2.6% compared to 10 hours of sleep. Fortunately, a night of long sleep (12 hours) helped restore metabolism more effectively. It also seems that poor sleep may increase muscle loss in turn can slow down your metabolism. If you struggle to fall asleep, stop your TV cell phone computer etc. at least one hour before bed.

4. Eat More Protein-Rich Foods

Eating more protein-rich foods can help fight a slowing metabolism. That’s because your body burns more calories while consuming, digesting and absorbing protein-rich foods.  In fact, studies have shown that consuming 25–30% of your calories from protein can boost your metabolism by up to 80–100 calories per day, compared to lower protein diets.  A protein-rich diet can fight an aging metabolism by preserving muscle.

5. Make Sure You Eat Enough Food

A low-calorie diet can slow down your metabolism by switching your body into “starvation mode”. While dieting has its benefits when you’re younger, maintaining muscle mass is more important with age. Older adults also tend to have a lower appetite, which may decrease calorie intake and slow metabolism. If you struggle to eat enough calories, try eating smaller portions more frequently. It is also great to have high-calorie snacks like cheese and nuts handy.

6. Drink Green Tea

Green tea can increase your metabolism by 4–5%.This is because green tea contains caffeine and plant compounds, which have been shown to increase your resting metabolism. A study in 10 healthy men found that drinking green tea three times daily increased their metabolism by 4% over 24 hours. (The author has his own study and views)