Cardiorespiratory fitness is widely recognized as a key health indicator due to its well-documented benefits. The growing accessibility of wearables and health-monitoring devices allows for the collection of objective data points – such as heart rate, VO2 max, and heart rate variability, which can inform individual health journeys and potentially be integrated into risk assessments.
Musculoskeletal fitness has also been extensively researched and is increasingly emphasized by clinicians as a marker of wellness and a target for health maintenance. Skeletal muscle is essential for functional abilities that support mobility, independence, and overall quality of life, particularly as we age. Strength and resistance training help preserve these abilities, reduce mortality and morbidity, and reinforce the connection between musculoskeletal health and longevity.
Given that skeletal muscle comprises approximately 40% of body mass in healthy individuals, understanding its role in health and risk assessment is increasingly relevant.1 This article explores musculoskeletal fitness, focusing on the importance of muscle strength and mass and potential impact in an insurance setting.
The musculoskeletal system is primarily responsible for physical function and mobility. Skeletal muscle enables us to perform a wide range of activities, ranging from essential daily tasks – such as bathing, dressing, eating, or getting from place to place – to more complex recreational and athletic pursuits that contribute to both health and personal fulfillment. In many occupations, a healthy musculoskeletal system is often crucial, where tasks are not only cognitive in nature but also require physical strength and endurance.
Beyond mobility, skeletal muscle serves as a critical source of protein (amino acids) and plays a key role in metabolic, cellular, and immune functions. It also helps regulate insulin and glucose metabolism.
The crucial role of muscle becomes even more apparent in the context of acute and chronic illnesses or traumatic injury, where the body’s demand for recovery and healing increases significantly. Higher muscle mass has been linked to improved survival rates in patients with chronic conditions, sepsis, cancer, ICU admission or those with severe burns.2,3
Regarding insulin and glucose metabolism, muscle tissue is the primary site for glucose and triglyceride utilization. Research indicates that greater muscle mass and strength and higher muscle-to-fat ratio are associated with lower insulin resistance, while low muscle strength has been linked to a higher prevalence of type 2 diabetes.2,4
Age-related loss of skeletal muscle mass (known as sarcopenia) is associated with osteopenia (lower bone density). Muscle contractions and weight-bearing exercises apply mechanical force to bones, stimulating bone formation and maintaining bone density. This mechanical force, along with muscle contraction, plays a crucial role in maintaining bone health.3
After age 30, muscle mass declines by an estimated 3% to 8% per decade in individuals who do not participate in strength or resistance training, with an even greater decline after age 60.4 Bone mineral density also decreases by 1% to 3% annually.5 In addition to muscle loss, declining muscle strength – referred to as dynapenia – further increases the risk of frailty, falls, injury, and loss of mobility and independence as we age.
With cardiovascular disease, stroke, and cancer among the leading causes of death,6 addressing chronic disease management and prevention, physical inactivity, and sedentary behavior is essential – not only for improving patient outcomes but also for insurers assessing long-term risk.
Given the crucial role skeletal muscle plays in overall health, musculoskeletal health and fitness deserves greater attention. Exercise guidelines in both the UK and US recommend engaging in strength-based activities targeting all major muscle groups – legs, hips, back, abdomen, chest, shoulders, and arms – at least twice a week.7,8
Proper strength-training techniques and weight-bearing exercises help mitigate muscle loss, maintain strength, and preserve bone density, all of which are critical for sustaining physical mobility, function, and independence as we age.
Insurers have a unique opportunity to promote health and wellness through education and preventive initiatives. Emphasizing the importance of musculoskeletal fitness and the benefits of strength and resistance training can encourage policyholders to adopt healthier habits, potentially leading to positive outcomes for both the policyholder and the insurer.
Muscle mass and strength provide valuable insights into body composition, functional abilities, and metabolic health, enhancing current risk assessment methods.
For example, within a given BMI range, the muscle-to-fat ratio can help refine risk segmentation. Highly muscular individuals may be misclassified under traditional BMI metrics, and as body composition shifts with age, assessing muscle mass relative to fat can offer a more precise evaluation of health risk. These considerations align with the ongoing reassessment of BMI as a measure of adiposity.9
In claims assessments, muscle strength and mass serve as non-traditional risk factors that may improve evaluations of prognosis, recovery timelines, and return-to-work potential for acutely or chronically ill individuals. Conversely, prolonged immobility due to acute traumatic injuries or chronic illnesses can contribute to musculoskeletal decline, further impacting health outcomes and claim duration.
Assessing muscle mass and strength involves several techniques, each with varying accuracy, accessibility, and cost. While this poses challenges, it does not diminish the potential value of incorporating musculoskeletal health into underwriting or claims – provided the technique used is accurate, validated, affordable, and accessible.
Body composition, including fat, muscle, and bone mass, can be measured using dual-energy x-ray absorptiometry (DEXA), bioelectrical impedance analysis, CT, or MRI. DEXA scans are sometimes available for osteoporosis screening, whereas CT and MRI are not routinely used for this purpose. Additionally, smart scales connected to wearable devices can provide estimates of body composition.
Handheld dynamometers are another tool, offering a portable means of evaluating grip strength, which research has identified as a strong indicator of overall muscle strength. Studies have linked poor hand-grip strength to adverse clinical outcomes, while emerging evidence also suggests that lower-limb weakness correlates with increased mortality risk.2,4
Insurers should evaluate the feasibility, accuracy, accessibility, and affordability of these measurement techniques within specific risk segments such as the older populations, or with relevance to specific products – such as longevity and frail-care cover – based on regional and market considerations. While some markets may not yet have access to suitable methods, advancements in technology may expand these capabilities in the future.
Assessments regarding muscle strength, mobility, gait, or endurance can provide insights that can help fine-tune risk for older lives or segment risks across preferred, standard, and substandard pools. Table 1 lists functional assessments that can be used at underwriting or claims stage depending on the risk presented.
Table 1: Common Methods for Assessing Functional Capacity and Musculoskeletal Function
Assessment of Exercise Functional Capacity or Endurance
| Standard Bruce treadmill protocol | Widely used for cardiac stress testing, involving progressive increase in speed and incline every three minutes. |
| Modified Bruce protocol, Balke, Naughton, and other individualized protocols | Treadmill protocols using lower rate of exercise provocation – used to accommodate older patients or those who are deconditioned. |
| Six-minute walk test | A submaximal exercise test that can be used to assess functional capacity and endurance in cardiopulmonary or older patients. |
Assessment of Gait
| Assessment of gait speed | Timed walk over short distances, such as 4 m. Is a non-aerobic exercise that can gauge functional status. |
| Visual assessment of gait pattern | Visual assessment of gait speed or inspection for irregularities, such as shuffling gait, walking with imbalance, stooped posture, flat-footedness, foot drop, Trendelenburg or compensated Trendelenburg gait, kyphoscoliotic changes that may shift center of mass and pelvic obliquity. |
Assessment of Muscle Strength
| Assessment of grip strength | Evaluated using handheld dynamometer, squeezed tightly, with multiple readings obtained from both hands. Reflects overall muscle strength. |
| Assessment of lower limb strength | Can evaluate by assessing quadricep strength in performing walking lunges, or a double leg squat. Can evaluate number of sit-to-stand during 30 s to assess for leg strength and endurance. |
Evaluation of Balance
| Standing balance tests | Examples include standing on one foot for 10 s minimum, standing with eyes closed, tandem standing, Romberg’s test, or performance of tandem walking. |
| Short physical performance battery | A battery of 3 tests that assess lower extremity function: evaluation of gait speed, performance of repeated chair rise, and standing balance. |
| Timed up and go test | Rise from armchair, walk 10 ft, turn around, and walk back to chair. Integrates assessment of gait speed and balance. |
Functional assessments provide valuable insights into mobility, strength, and overall physical function, particularly in aging populations or individuals recovering from illness or injury. Many of these assessments currently require in-person or online evaluation by a trained professional, making cost and efficiency key considerations for insurers. However, as the industry moves toward digitization, advancements in medical tools and wearables with embedded sensors may streamline data collection on gait, balance, and fall risk – potentially enhancing underwriting processes.
For claims assessments, functional capacity evaluations are already integrated into some markets and are typically conducted by occupational therapists. These evaluations frequently assess grip strength, muscle strength, and muscle wasting, all of which can provide essential insights.
For example, a claimant recovering from a prolonged ICU stay or chemotherapy may exhibit reduced grip strength and muscle wasting, requiring additional rehabilitation time. Incorporating these factors into claims assessments allows insurers to set more realistic return-to-work expectations and tailor interventions to support recovery.
While a range of functional assessments exist, insurers should weigh their time, cost, and effectiveness based on the level of risk exposure. For example:
Strategic selection of assessments, coupled with evolving technology, could help insurers enhance onboarding process and refine risk segmentation, leading to more personalized underwriting and claims strategies.
Musculoskeletal fitness, particularly muscle strength and mass, along with functional assessment tools, represents a valuable yet underutilized set of risk factors. These health indicators can enhance risk profile differentiation, better inform on return-to-work potential, and improve overall prognoses.
Insurers are encouraged to explore non-traditional risk factors where they align with accuracy, feasibility, and market relevance. As technology continues to evolve, ongoing evaluation of these advancements may reshape the way insurers approach, assess, and personalize risk management strategies.
RGA experts are eager to engage with clients to better understand and tackle the industry’s most pressing challenges together. Contact us to learn more about RGA's capabilities, resources, and solutions.
