M6(2) Aerobic Exercise and Fitness in Older Adults

interest in PA

we are interested in PA as it is associated w/ many health benefits that are relevant to older ages;

in older individuals, PA can be a strong modulator for diseases

• CVD

• Sarcopenia

• Diabetes

• Obesity

• Osteoporosis

• Pulmonary Disease

chronic disease and aging

by age 65-79 a majority of the population will have one or more diseases

chronic conditions

top 4 chronic conditions among adults and seniors in Canada:

1. high blood pressure

2. arthritis

3. heart disease (older adults) chronic pain (adults)

4. diabetes (older adults) depression (adults)

exercise and life expectancy

more exercise is associated with increase in years of life gained

• PA equivalent to brisk walking for ~75 min/week was associated w/ a gain in 1.8 years in life expectancy

• PA above recommended minimum 150 min/week associated w/ an overall gain in 3.4-4.5 years in life expectancy

SB and PA

SB is a separate construct from PA level

• one school of thought: efforts should be made to inc PA levels and dec SB as they have independent influences on health (Banoski et al 2011)

other data

other data suggests cardiorespiratory fitness and MVPA are significantly associated w/ better health outcomes, while SB is not

• Stahokostas et al. 2015

• Amgassa et al. 2019

Stathokostas et al 2015

using linear regressions for # chronic conditions, # chronic cardiovascular conditions, and BMI; found that

• SB → not related to CD, CVD, BMI

• total PA → related to some CVDs

• maximal oxygen consumption → correlated to ALL 3 conditions

aerobic capacity

aerobic capacity is essential to maintaining a minimum level of fitness (required for performing activities of daily living)

• VO₂max = HR_max x SV_max x (a-vO₂ diff)

Murias et al 2010

study by Murias et al 2010 to examine cardiorespiratory fitness w/ endurance training in older adults and younger adults

• 45 minute cycling sessions at approx 70% VO₂max

HRmax

maximal heart rate declines with age

• SV must compensate to maintain same Q

Murias findings

men:

• peak Q

  • increased

    • younger adults started at an absolute higher baseline compared to older adults

  • remained elevated post training

• peak a-vO₂ diff

  • inc but not as much as women

  • remained elevated post training

women:

• peak Q

  • increased

    • younger adults started at an absolute higher baseline compared to older adults

  • remained elevated post training

• peak a-vO₂ diff

  • inc

  • remained elevated post training

• VO₂

  • increased but not as much as men

type of exercise

then type of exercise and how much of it matters in reaping the benefits from PA

• anything that improves aerobic fitness is better (inc cardiorespiratory endurance)

  • walking, hiking, stairs, cycling, swimming

Izquierdo et al 2021

highlights that health is a combination of PA, genetics, and other influencing factors

• PA can increase health and decrease time of morbidity no matter what stage the individual start

• maintain younger physiology

PA and healthy aging

PA helps in healthy aging and can mitigate:

• oxidative damage

• inflammation

• mitochondrial dysfunction

• insulin-like growth factor signaling

• defective autophagy (cell cycling)

• myokine release

evidence supports that PA reduces chronic disease (sarcopenia, diabetes, CV disease, dementia, depression, etc)

PA recommendation

why should we recommend exercise

• prevents diseases (even for those that have treatments)

• serves as an adjunct to medical treatment (e.g. surgery)

• alternative for potentially harmful treatments

• main care strategy for conditions that have no other effective treatment (frailty, sarcopenia, dementia, disability)

inter-individual variability

different people respond differently to the same exercise program

• some show large improvements (responders), while others show little or no change (non-responders)

  • can change depending on what you are measuring

reasons for variability

several reasons for inter-individual variability

1. training stimulus insufficient

2. baseline fitness

3. sex differences

4. interaction of physiological, molecular, environmental factors

PA dosage

what’s the PA dose or degree of fitness needed to reduce risk of morbidity or all-cause mortality

Borg RPE scale

goes from 6-20, corresponds roughly to heart rate in healthy adults

• HRmax = 220 - age 

• OR

• HRmax = 207 - (0.7 x age)

Evidence to Develop Exercise Recommendations for Older Adults

2007 article by Paterson, Jones, Rice to provide insights in how PA influences aging and offers evidence-based exercise guidelines for older adults

1. epidemiological evidence on PA

2. exercise prescription

3. volume and dose response

epidemiological evidence on PA

Intensity matters:

• To reduce health risks and increase longevity, physical activity must meet a minimum intensity:

  • Moderate: ~5 times per week

  • Moderately vigorous: ~3 times per week

• This corresponds to >50% VO₂max, typically in the 60–70% range for exercise training

CR fitness increase is key:

• Health benefits (reduced morbidity/mortality) are greatest when activity actually improves cardiorespiratory fitness, not just moves you slightly.

exercise prescription

• Brisk walking is effective for improving CR fitness:

  • Speed: 3–3.5 mph (~12–14 ml/kg/min VO₂)

  • Intensity relative to VO₂max: 60–70% VO₂max

  • This matches the moderately vigorous training zone for older adults.

• Takeaway: Walking at this pace can serve as a practical, achievable exercise prescription for older adults to improve cardiovascular health.

volume and dose response

• Duration and frequency matter linearly:

  • More total activity → greater reduction in risk.

• Threshold for significant benefit:

  • ~1000 kcal/week (4200 kJ) of physical activity is associated with 20–30% reduction in relative risk of morbidity and mortality.

• Supplement to light activity:

  • Benefits are in addition to everyday light activity (e.g., ADLs like walking around the house, chores).

habitual PA

simply being more active in daily life (habitual physical activity, like walking around the house or doing chores) does not prevent the natural age-related decline in cardiorespiratory (CR) fitness

• supported by Stathokostas et al., 2007, Hollenberg et al., 2006, Fleg et al., 2005

habitual PA and CR decline

to meaningfully slow or reverse CR fitness decline, older adults need structured exercise at moderate-to-vigorous intensity, not just light habitual activity.

• everyday low-intensity activity (ADLs) is beneficial for health, but higher-intensity exercise is necessary to maintain or improve VO₂max

volume adjustment

from Strasser and Burtscher (2018) regarding adjusting exercise volume:

1. equivalence of intensity and duration

2. high intensity bouts

equivalence of intensity and duration

High-intensity activity burns more energy per unit time, so less time is needed to achieve the same total energy expenditure.

• 150 min/week of moderate-intensity activity ≈ 75 min/week of high-intensity activity

high intensity bouts

short, high-intensity bouts of exercise can be effective

• Even 5–10 minutes/day of vigorous exercise (≥6 METs) can significantly reduce:

  • All-cause mortality

  • Cardiovascular disease risk

• This is supported by Lee et al., 2014, as cited in Strasser and Burtscher (2018)

CRF

cardiorespiratory fitness is important:

1. chronic conditions

2. cancer

3. pre-operative benefits

4. healthy life years

CRF and chronic conditions

Aerobic exercise improves CRF in patients with:

• COPD (Chronic Obstructive Pulmonary Disease)

• HF (Heart Failure)

Even small muscle group exercises (e.g., arms, legs) can improve fitness and have potential for progression to larger muscle groups.

CRF and cancer

Higher aerobic fitness is associated with a reduced risk of certain cancers.

• Physical activity in cancer survivors can:

  • Improve aerobic fitness

  • Lead to healthy body composition changes (e.g., reduced fat, maintained muscle)

  • Enhance quality of life (QoL)

• Reference: Fong et al., 2012 (cited in Strasser & Burtscher, 2018)

CRF and pre operative benefits

aerobic training before surgery can improve surgical outcomes and recovery by enhancing cardiovascular reserve.

CRF and healthy life years

muscle and strength training increase CRF and increase healthy life years

• decreases time for prevalence of diseases

• can reap benefits at any time w/ PA

mild exercise and reducing SB

evidence for benefits of mild exercise or reduction in sedentarism

• diabetes study (Yang et al)

• long-term cancer survivors study (Trinh et al., 2023)

diabetes study

study by Yang et al (doctoral dissertation)

• Finding:

  • Longer-duration, less vigorous exercise (mild-to-moderate intensity) produced the greatest improvements in cardiorespiratory (CR) fitness.

• Implication:

  • You don’t always need high-intensity exercise to improve CRF.

  • Sustained, moderate activity can be highly effective, especially for populations with chronic conditions like diabetes

long-term cancer

study by Trinh et al. 2023

• Finding:

  • Higher physical activity (PA) levels and lower sedentary behaviour were linked to better perceived cognitive function.

• Implication:

  • Even mild activity or simply reducing sitting time can have meaningful cognitive and health benefits for long-term survivors.

steps study

study by Aoyagi and Shephard (2009)

• Population: ~500 elderly participants in Nakanojo, Japan

• Design: Interdisciplinary study examining habitual physical activity (PA) and health

• Measurement: Specially adapted pedometer/accelerometer to quantify daily activity

steps study findings

threshold of activity for health benefits

• physical health

  • 20 minutes/day at >3 METs (moderate intensity)

  • linked to improvements in physical health (e.g. mobility, functional capacity)

• mental health

  • 5 minutes/day at 3 METs

  • linked to improvements in mental health (e.g. mood, cognitive function)

steps study implications

Even short bouts of moderate activity per day can yield meaningful health benefits for older adults.

• Supports the idea that total daily movement, not just structured exercise, matters for health in seniors.Even short bouts of moderate activity per day can yield meaningful health benefits for older adults.

• Supports the idea that total daily movement, not just structured exercise, matters for health in seniors.

key point

low intensity exercise associated w/

• improvements in fitness and mental health

• may result in less sedentary time