Bone Health and Osteoporosis

Bone health is a critical consideration when working with older adults. Osteoporosis and related fractures can dramatically impact quality of life, independence, and even survival. As a senior fitness specialist, understanding how to safely promote bone health through exercise is essential.

Understanding Bone Biology

Bone as Living Tissue

Bone is dynamic, living tissue that continuously remodels throughout life. Two types of cells drive this process:

Osteoblasts: Build new bone tissue

Lay down collagen matrix
Deposit calcium and other minerals
More active during growth and in response to mechanical loading

Osteoclasts: Break down bone tissue

Remove old or damaged bone
Release calcium into bloodstream
Become more active relative to osteoblasts with aging

In healthy adults, bone formation and resorption are balanced. With aging, resorption begins to exceed formation, leading to net bone loss.

Types of Bone

Cortical (compact) bone:

Dense outer layer of bones
80% of skeletal mass
Found in long bone shafts
Slower turnover rate

Trabecular (cancellous) bone:

Spongy interior structure
Found in vertebrae, pelvis, ends of long bones
Higher metabolic activity
More susceptible to age-related loss

Age-Related Bone Changes

Peak Bone Mass

Achieved by approximately age 30
Determined by genetics (60-80%) and lifestyle factors
Higher peak bone mass provides a larger "reserve" for age-related loss

Bone Loss Patterns

Women:

Accelerated loss in 5-7 years following menopause (2-3% per year)
Estrogen decline removes protective effect on bone
Can lose 20% of bone mass in first 5-7 years post-menopause
Rate stabilizes to about 1% per year thereafter

Men:

More gradual loss beginning around age 65-70
Approximately 0.5-1% per year
Testosterone decline contributes but is more gradual

Osteoporosis: Definitions and Diagnosis

WHO Definitions Based on DXA Scan

T-score compares bone density to healthy young adults:

Normal: T-score ≥ -1.0
Osteopenia (low bone mass): T-score between -1.0 and -2.5
Osteoporosis: T-score ≤ -2.5
Severe osteoporosis: T-score ≤ -2.5 with one or more fractures

Risk Factors for Osteoporosis

Non-modifiable:

Age
Female sex
Caucasian or Asian ethnicity
Family history
Small body frame
Personal history of fracture

Modifiable:

Low calcium and vitamin D intake
Sedentary lifestyle
Smoking
Excessive alcohol consumption
Low body weight
Certain medications (steroids, some anticonvulsants)

Fracture Risk Assessment

FRAX Tool: The Fracture Risk Assessment Tool estimates 10-year probability of major osteoporotic fracture and hip fracture based on clinical risk factors with or without bone mineral density.

Common fracture sites:

Vertebral (spine) - Often silent, leading to height loss and kyphosis
Hip - Most devastating, with significant mortality risk
Wrist (distal radius) - Often from falls on outstretched hand
Proximal humerus - From falls or direct trauma

Exercise for Bone Health

Principles of Bone-Loading Exercise

Bone responds to mechanical loading through mechanotransduction—cells sense mechanical strain and respond by building bone. Key principles:

1. Specificity

Bone adaptation is site-specific
Must load the bones you want to strengthen
Walking helps hip but not wrist bone density

2. Progressive Overload

Bone adapts to loads exceeding normal daily activities
Must progressively increase demands
Maintenance requires ongoing stimulus

3. Variety

Bone responds best to novel stimuli
Vary exercises, directions, and intensities
Adaptation decreases with repetitive, identical loading

4. Intensity Over Duration

Higher-intensity, shorter duration is more osteogenic
Multiple short bouts may be more effective than continuous loading
Quality over quantity

Effective Exercise Types for Bone Health

Weight-bearing impact activities:

Walking (moderate benefit)
Stair climbing
Dancing
Low-impact aerobics
Tennis, pickleball

Resistance training:

Targets specific bone sites
Most effective for spine and hip
Essential component of bone health programs

Balance training:

Reduces fall risk (thus fracture risk)
Does not directly build bone
Critical component of comprehensive program

Exercise Contraindications and Modifications for Osteoporosis

Higher-risk movements to avoid or modify:

Spinal flexion under load:

Crunches, sit-ups
Loaded forward bending
Toe touches
Rationale: Increases vertebral compression fracture risk

High-impact activities:

Jumping (for those with significant bone loss)
Running on hard surfaces
High-impact aerobics

Sudden, twisting movements:

Rapid rotation of spine
Golf swing modifications may be needed
Tennis serve adaptations

Safe alternatives:

Planks and bird-dogs instead of crunches
Hip hinge patterns with neutral spine
Chair-supported balance exercises
Lower-impact weight-bearing activities

Programming Guidelines

ACSM Recommendations for Bone Health

Weight-bearing endurance activities:

Moderate to high intensity
3-5 days per week
30-60 minutes per day

Resistance training:

Moderate to high intensity (60-80% 1RM)
2-3 days per week
8-12 repetitions
2-3 sets
Target major muscle groups, especially those attaching to hip and spine

Balance and mobility:

Daily or near-daily
Include static and dynamic balance challenges
Progress difficulty appropriately

Sample Weekly Schedule

Monday - Resistance Training

Lower body focus
Hip-dominant exercises (hip hinge, bridges)
Squat variations
Core stability (avoid flexion)

Tuesday - Weight-Bearing Cardio

Walking program
Stair climbing if appropriate
Light balance challenges

Wednesday - Active Recovery

Gentle stretching
Tai chi or yoga (modified for osteoporosis)

Thursday - Resistance Training

Upper body focus
Rowing movements
Pressing movements
Core stability continuation

Friday - Weight-Bearing Cardio

Dance class
Walking with intervals
Balance circuit

Saturday/Sunday - Active Lifestyle

Recreational activities
Walking
Gardening

Exercise Intensity Considerations by Bone Status

Normal bone density:

Full range of weight-bearing activities
Progressive resistance training
Jump training may be appropriate
Focus on building bone "reserve"

Osteopenia:

Most weight-bearing activities appropriate
Resistance training with gradual progression
Avoid high-impact unless cleared
Emphasis on fall prevention

Osteoporosis without fracture:

Lower-impact weight-bearing activities
Resistance training with careful supervision
Strict avoidance of high-risk movements
Strong emphasis on balance and fall prevention

Osteoporosis with fracture history:

Very conservative approach
Medical clearance essential
Focus on functional movements and fall prevention
Resistance training under close supervision
May require physical therapy collaboration

Nutrition for Bone Health

While not your primary scope as a fitness professional, understanding nutrition basics helps you make appropriate referrals:

Calcium:

1200 mg/day recommended for adults over 50
Food sources preferred over supplements when possible
Dairy, fortified foods, leafy greens

Vitamin D:

800-1000 IU/day minimum for older adults
Many older adults are deficient
Sun exposure, fortified foods, supplements

Protein:

Adequate intake supports bone matrix
1.0-1.2 g/kg/day for older adults
Works synergistically with exercise

Key Takeaways

Bone is dynamic tissue that responds to appropriate loading throughout life
Site-specific loading is required—exercises must target bones of concern
Osteoporosis requires exercise modification, not exercise avoidance
Avoid loaded spinal flexion in clients with low bone density
Fall prevention is as important as bone-building for fracture risk reduction
Resistance training is essential for bone health, particularly at hip and spine
Progressive overload applies to bone just as it does to muscle
Refer appropriately for nutrition guidance and medical management