Organ Reserve - an important aspect of Healthy Ageing
In 1838, two British steamships competed to be the first to cross the Atlantic using continuous steam power. The crossing was quite dramatic as the SS Sirius ran out of fuel and had to burn cabin furniture and even one of its masts to complete the journey, which took 18 days.
The SS Great Western arrived in New York one day after the Sirius but completed the journey in 15 days and arrived with 200 tons of coal as reserve. This reserve enabled the ship to comfortably weather any delays, like unexpected storms.
We too need reserve in our organs to overcome unexpected illness.
And I am not talking about fat as a reserve. An obese person with loads of fat cannot compete with a lean marathon runner. I am talking about functional reserve. The ability of the organ to rise up to unexpected demands like an infection, surgery, or stress. If there is no functional reserve, it is already functioning at maximal capacity. Like a car with no reserve power to accelerate to get out of an impending accident. The more reserve we have in muscle, immune system, liver, brain, heart, lungs, or kidneys, the better we can perform and withstand infection, stress, or surgery. Another way to look at it is that it is about resilience. If that organ is stressed by infection or illness, how easily does it recover? It is another way of looking at health.
Let me explain with a simple example.
The lungs. A smoker loses lung reserve with each year of smoking. When young, the lungs are healthy and have a lot of reserve, i.e., more than you need to function with daily activities, including exercise. But as the lungs become more damaged, they lose that extra capacity or reserve, and the smoker starts to get breathless.
Another example is the heart.
A 20-year-old's heart can pump about 10 times more blood than required for survival. After age 30, an average of 1% of this reserve is lost each year. Regular exercise (both aerobic and strength training) can help maintain cardiovascular and respiratory reserves.
Kidney function also naturally declines with age.
Reduced reserve makes older adults more vulnerable to kidney injury. Some medications can also compromise kidney function. The commonest over-the-counter medication is the group of non-steroidal anti-inflammatory drugs, e.g., ibuprofen. There are others that are prescription medications that you need to discuss with your doctor if you are taking them.
The brain undergoes structural changes as we age.
Research shows that we can maintain brain reserve with activities like social engagement and volunteering and help preserve cognitive functions. Keeping your mind active with puzzles, reading, and learning new skills can also help. A healthy gut microbiome also plays a key role in maintaining or even improving brain function. The reverse is also true: an unbalanced gut microbiome can aggravate anxiety and depression, affect memory, and even contribute to Alzheimer's disease.
Other organs also need reserve capacity, even the liver.
This organ has multiple functions. One major one is detoxification of toxins like alcohol and environmental toxins. Once the reserve capacity is exhausted, the liver cannot detoxify as well, and these people start to feel ill with toxin exposure.
As we age, our organ reserve diminishes anyway, so it is important to take action to reduce the rate at which we lose reserve.
Building reserves in your organs is like building a savings account.
The earlier you start, the better, but now is better than not starting at all. This series of newsletters on Healthy Aging will show ways to build reserve in your organs.
The captain of the SS Great Western planned and made sure of reserve capacity in his ship to get to New York faster than his competitor, who did not have the reserve. We all can build reserve functional capacity to survive and thrive in our journey through life. Future newsletters will cover in detail how we can build that reserve.
References:
1. Organ reserve, excess metabolic capacity, and aging PMID: 29335816
2. Network physiology in aging and frailty. The grand challenge of physiological reserve in older adults. PMID: 36925570
3. Structural and functional changes with the aging kidney PMID: 26709059
Medical Disclaimer:
This newsletter is for general informational purposes only and does not constitute medical advice. The content should not replace professional medical advice, diagnosis, or treatment. Always seek the guidance of your doctor or other qualified health professional with any questions you may have regarding your health or a medical condition. Never disregard professional medical advice or delay seeking it because of something you have read in this newsletter. Reliance on any information provided here is solely at your own risk.
