On Physical Functioning, Quality-of-Life and Euthanasia, Part III: Meaningful Physical Activity

Physical Activity as the “Glue” of Lifestyle

Independent living requires cognitive health, good physical functioning and psychological well-being, traits that form what people truly value: the ability to live autonomously. One must simultaneously exceed minimum thresholds of functioning in all 3 domains, because deficits in any of these domains cannot be compensated for by strengths in the others. Severe cognitive decline renders physical health irrelevant. Inability to execute the tasks of daily living cannot be overcome with intelligence. And neither cognitive ability nor physical functioning can surmount severe mental illness. 

 

Ng, et al., examined lifestyle risk factors through the lens of association with age of first chronic disease, adjusted for sociodemographic and health factors.[Ng, John]

 

• Smoking (HR 3.86 for heavy smoking, 1.20 for former light smokers)
• Obesity vs normal BMI (HR 1.43 overweight, 1.80 class I, 2.70 class II, 3.04 class III)
• Social isolation (HR 1.50)
• Alcohol consumption vs light drinker (HR 1.28 non-drinker, 1.22 heavy drinker)
• Few fruits or vegetables (HR 1.15 relative to 6 or more)
• Physical inactivity (HR 1.08)
• Extreme life stress vs no stress (HR 0.98)

 

Cognitive decline and dementia are threats for independent living. Mixed evidence suggests that regular exercise is associated with smaller decreases in cognitive decline, particularly episodic memory and verbal fluency.

[Zhao, Ahlskog, Begde, Blondel]

 

• Physical activity (HR 0.65 for cognitive decline, HR 0.82 for dementia)
• Physical activity in midlife reduces risk of mixed (HR 0.43) and cerebrovascular dementias (HR 0.47), reducing the rate of cognitive decline while maintaining the strength, balance and mobility. 
• Exercise significantly improves activities of daily living and balance, but has more limited benefits on walking and visuospatial function.

 

Social isolation impacts independent living through its effects on cognitive stimulation and motivation for self-care. Poor diet and sleep disruption significantly affect both cognitive function and physical capacity over time.[Holt]

 

Altogether, studies suggest that smoking, obesity and excessive alcohol consumption lead to disability through cardiovascular, pulmonary and musculoskeletal conditions that affect physical functioning. Physical activity directly maintains strength, balance, coordination and mobility by preventing sarcopenia, maintaining bone density and preserving cardiovascular capacity, all of which promote physical resilience. 

 

Interactions Between Risk Domains 

But why is exercise the “glue” of lifestyle change? Physical activity seems synergistic the other lifestyle domains, more so than the other domains within themselves. [Ussher, Sewell, McGranahan, Pearce, Schuch, Xu, Coll-Risco, Garcia-Hermoso, Wilcox]

 

• Sleep quality enhancement through effects on sleep architecture
• Reduced anxiety and depression
• Social connection through group activities
• Association with dietary changes but not as a causal pathway
• Exercise reduces tobacco cravings, but may not promote long-term abstinence

 

Social isolation has significant impact on both cognitive stimulation and motivation. [Teo, Park, Cooper, Martin]

 

• Social circles influence dietary and exercise habits,
• Social connection helps in managing anxiety and depression.

 

There is limited evidence on an association between diet and independent living, though absence of evidence is not evidence of absence. Data on biomarkers related to diet aren’t as potent predictors of mortality as exercise capacity. [Itani, Jin, Goldman]

 

• Physical functioning is a better predictor of mortality than biometric measures related to diet,
• Exercise protects against mortality even if someone has an unhealthy diet. 
• Dietary interventions alone cannot preserve physical functioning, muscle hypertrophy depends on the availability of amino acids and exercise to stimulate protein synthesis. 

 

Pure cognitive interventions lack preservation of physical functioning, though the combination of good nutrition, physical activity and mental and social engagement is believed to promote brain health.

 

Meaningful Physical Activity

“Meaningful” physical activity is not simply being active, it is characterized by connection — to people, nature or emotional transcendence — in a way that is intrinsically motivating and provides spiritual release. The source of spiritual release can be competitive sports, hikes in nature, paddling or any activity that provides physical, cognitive and emotional immersion – something completely engrossing mind, body and spirit. The defining sensation is that the trials and tribulations of daily life disappear from mind. 

 

Thirty minutes on an elliptical trainer while listening to TV is a workout, but generally doesn’t provide spiritual release. Playing a musical instrument is not what most think of as exercise, but does provide spiritual release. Thus, not all exercise is meaningful, nor are all meaningful activities exercise. 

 

This may explain why certain forms of physical activity are popular and, perhaps, why many people who take out gym memberships at the New Year don’t stick with it. Many of my patients have viewed exercise as a just another chore, usually because they try exercises that aren’t meaningful to them. Meaningful forms of exercise:

 

• Connect to Others: Team sports, exercise classes or group activities involve social engagement; and/or
• Connect to Nature: Activities like hiking, gardening, or outdoor sports that provide communion with the natural world; and/or
• Connect to Transcendence: Activities that create "flow states" where individuals experience full presence and engagement. 

 

Summary

They say you can’t escape death and taxes, and almost everyone eventually faces some measure of disability. Debate over euthanasia focuses on “terminal conditions”, but what euthanasia really offers is the ability to avoid extreme disability that precedes death from incurable diseases. Sadly, many people not only endure such a fate, but are also stripped of all their wealth due to the costs of long term care. Some two-thirds of Americans leave nothing to their heirs. 

 

Having a healthy lifestyle provides no guarantee that one won’t be disabled, but lifestyle, starting with meaningful physical activity, offers the surest path to “compression of morbidity”, to minimizing the period of time in life when one’s survival is dependent on others. 

 

Last Word on the Role of Pets 

Companion animals are believed to be good for human health and well-being, and pet owners are more active than non-owners.[Hughes, Martins, Maurice, Northrope] Our dog, Casi, had a palpably more positive attitude towards going on a walk with her “whole pack” than she did with just one of us, eagerly walking 3-5 times further when we were all together. 

 

Dogs appear to instinctively know: go outside and play to get hungry, enjoy meals with your family, get plenty of sleep, don’t bark too much and there’s nothing better than hanging with your pack. There is, however, one point where dog wisdom dramatically diverges from mine – I don’t drink out of a puddle. 

 

 

References

Ng R, et al. Smoking, drinking, diet and physical activity—modifiable lifestyle risk factors and their associations with age to first chronic disease. Intl J Epidemiology 2020;49(1):113–130. doi: 10.1093/ije/dyz078

 

John U, et al. Behavior‐related health risk factors, mental disorders and mortality after 20 years in a working aged general population sample. Sci Reports 2023;13:16764. doi:10.1038/s41598-023-43669-8

 

Zhao C, et al. Dietary patterns, physical activity, sleep, and risk for dementia and cognitive decline. Curr Nutr Rep 2018;7(4): 335–345. doi:10.1007/s13668-018-0247-9.

 

Ahlskog JE, et al. Physical exercise as a preventive or disease-modifying treatment of dementia and brain aging. Mayo Clin Proc 2011;86(9):876-884. doi:10.4065/mcp.2011.0252. 

 

Begde A, et al. Does physical exercise improve the capacity for independent living in people with dementia or mild cognitive impairment: an overview of systematic reviews and meta-analyses. Aging Mental Health 2022;26(12):2317–2327. https://doi.org/10.1080/13607863.2021.2019192

 

Blondel SJ, et al. Does physical activity prevent cognitive decline and dementia?: A systematic review and meta-analysis of longitudinal studies. BMC Public Health 2014, 14:510. http://www.biomedcentral.com/1471-2458/14/510

 

Holt-Lunstad J, et al. Social relationships and mortality risk: a meta-analytic review. PLoS Med 7(7): e1000316. doi:10.1371/journal.pmed.1000316

 

Ussher MH, et al. Exercise interventions for smoking cessation. Cochrane Database Systematic Rev 2019;10. Art. No.: CD002295. DOI: 10.1002/14651858.CD002295.pub6.

 

Sewell KR, et al. Relationships between physical activity, sleep and cognitive function: a narrative review. Neurosci Biobehav Rev 2021;130:369-378. doi: 10.1016/j.neubiorev.2021.09.003.

 

Pearce M, et al. Association between physical activity and risk of depression: a systematic review and meta-analysis. JAMA Psychiatry 2022;79(6):550-559. doi: 10.1001/jamapsychiatry.2022.0609.

 

McGranahan MJ, O’Connor PJ. Influence of regular physical activity on sleep. Curr Top Behav Neurosci 2024:67:309-328. doi: 10.1007/7854_2024_503.

 

Schuch FB, et al. Exercise as a treatment for depression: A meta-analysis adjusting for publication bias. J Psychiatr Res 2016;77:42-51. doi:10.1016/j.jpsychires.2016.02.023.

Xu

 

Coll-Risco I, et al. The influence of an exercise program in middle-aged women on dietary habits. The FLAMENCO project. Menopause 2022;29(12):1416-1422. doi: 10.1097/GME.0000000000002071.

Garcia-Hermoso A, et al. Is adherence to the Mediterranean diet associated with healthy habits and physical fitness? A systematic review and meta-analysis including 565 421 youths. Br J Nutr 2022;128(7):1433-1444. doi: 10.1017/S0007114520004894.

 

Wilcox S, et al. Do changes in physical activity lead to dietary changes in middle and old age? Am J Prev Med. 2000;18(4):276-83. doi: 10.1016/s0749-3797(00)00117-3.

 

Teo AR, et al. The role of social isolation in social anxiety disorder: a systematic review and meta-analysis. J Anxiety Disord 2013;27(4):353-64. doi: 10.1016/j.janxdis.2013.03.010.

 

Park C, et al. The effect of loneliness on distinct health outcomes: A comprehensive review and meta-analysis. Psychiatry Res 2020;294:113514. doi: 10.1016/j.psychres.2020.113514.

 

Cooper M, et al. Effectiveness and active ingredients of social prescribing interventions targeting mental health: a systematic review. BMJ Open 2022;12(7):e060214. doi: 10.1136/bmjopen-2021-060214.

 

Martin AF, et al. The impact of self-isolation on psychological wellbeing in adults and how to reduce it: A systematic review. PLoS One 2025;20(3):e0310851. doi: 10.1371/journal.pone.0310851.

 

Itani O, et al. Short sleep duration and health outcomes: a systematic review, meta-analysis, and meta-regression. Sleep Med 2017;32:246-256. https://doi.org/10.1016/j.sleep.2016.08.006.

 

Jin Q, et al. Association of sleep duration with all-cause and cardiovascular mortality: A prospective cohort study. Frontiers Pub Health 2022;10:880276. doi: 10.3389/fpubh.2022.880276

 

Goldman N, et al. What Matters Most for Predicting Survival? A Multinational Population-Based Cohort Study. PLoS ONE 2016;11(7): e0159273. doi:10.1371/journal. pone.0159273

 

Hughes MJ, et al. Companion animals and health in older populations: A systematic review. Clin Gerontol 2020;43(4):365-377. doi: 10.1080/07317115.2019.1650863. 

 

Martins CF, et al. Pet's influence on humans' daily physical activity and mental health: a meta-analysis. Frontiers Public Health 2023;11:1196199. doi: 10.3389/fpubh.2023.1196199. 

 

Maurice C, et al. Dog ownership and mental health among community-dwelling older adults: A systematic review. Int J Geriatr Psychiatry 2022;37(11):10.1002/gps.5815. doi: 10.1002/gps.5815.

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Northrope K, et al. The relationship between attachment to pets and mental health and wellbeing: A systematic review. Animals (Basel) 2025;15(8):1143. doi: 10.3390/ani15081143.