2.7: Physical Activity is Safe for Almost Everyone

Physical Activity is Safe for Almost Everyone

Most people are not likely to be injured when doing moderate-intensity activities in amounts that meet the Physical Activity Guidelines. However, injuries and other adverse events do sometimes happen. The most common problems are musculoskeletal injuries. Even so, studies show that only one such injury occurs for every 1,000 hours of walking for exercise, and fewer than four injuries occur for every 1,000 hours of running.

Both physical fitness and the total amount of physical activity affect the risk of musculoskeletal injuries. People who are physically fit have a lower risk of injury than people who are not. People who do more activity generally have a higher risk of injury than people who do less activity. To do physical activity safely and reduce the risk of injuries and other adverse events, people should:

Include Warm-up and Cool-down Activities

Warm-up and cool-down activities are an important part of a person’s physical activity plan. Commonly, the warm-up and cool-down involve doing an activity at a slower speed or lower intensity. A warm-up before moderate vigorous-intensity aerobic activity allows a gradual increase in heart rate and breathing at the start of the activity. A cool down after activity allows a gradual decrease at the end of the episode. A warm-up for muscle-strengthening activity commonly involves doing exercises with lighter weight.

Choose Appropriate Types and Amounts of Activity

People can reduce their risk of injury by choosing appropriate types of activity. The safest activities are moderate intensity, low impact, and don’t involve purposeful collision or contact. Walking for exercise, gardening or yard work, bicycling or exercise cycling, dancing, swimming, and golf are activities with the lowest injury rates. In the amounts commonly done by adults, walking (a moderate–intensity and low-impact activity) has a third or less of the injury risk of running (a vigorous-intensity and higher-impact activity).

The risk of injury for a type of physical activity can also differ according to the purpose of the activity. For example, recreational bicycling or bicycling for transportation leads to fewer injuries than training for and competing in bicycle races. People who have had a past injury are at risk of injuring that body part again. The risk of injury can be reduced by performing appropriate amounts of activity and setting appropriate personal goals. Performing a variety of different physical activities may also reduce the risk of overuse injury. The risk of injury to bones, muscles, and joints is directly related to the gap between a person’s usual level of activity and a new level of activity.

Increase Physical Activity Gradually Over Time

Scientific studies indicate that the risk of injury is directly related to the gap between a person’s usual level of activity and a new level of activity. This gap, known as the "amount of overload," can be minimized by gradually increasing physical activity, allowing the body time to adapt and recover.

When increasing physical activity to meet the guidelines or personal goals, it should be done gradually, regardless of the person's current level. The following guidelines provide general recommendations for individuals with low levels of physical activity:

1. Start with moderate-intensity aerobic activity: For those with low fitness levels, begin with light to moderate activity, avoiding vigorous activities like running or shoveling snow.
2. Increase duration and frequency first: Gradually increase the number of minutes per session and the number of days per week of moderate-intensity activity. After building consistency, intensity can be increased if desired.
3. Use relative intensity: Aim to exercise at an intensity level appropriate for your fitness level. Avoid overexertion, especially in the early stages.
4. Be mindful of the rate of increase: Increase activity by no more than 10 percent per week to minimize the risk of injury. For example, a 20-minute increase in activity per week is safer for someone doing 200 minutes of activity weekly than for someone doing only 40 minutes.
5. Consider individual factors: Age, fitness level, and previous experience will influence how quickly you can increase your activity. Youth and young adults can generally increase activity more quickly than older adults, who may need 2 to 4 weeks to adapt.

Approaching physical activity realistically is key to avoiding the risks of unaccustomed exercise. Jumping into high-intensity workouts or heavy lifting too soon can lead to injuries and fatigue, discouraging long-term progress. To reduce these risks, focus on gradually building up your fitness. Start with lighter, shorter sessions and gradually increase duration, intensity, and weight. This will allow your body to adapt to the new demands, reduce the risk of injury, and help you establish a sustainable fitness routine.

Use Protective Gear and Appropriate Equipment

Using personal protective gear can reduce the frequency of injury. Personal protective gear is something worn by a person to protect a specific body part. Examples include helmets, eyewear and goggles, shin guards, elbow and knee pads, and mouth guards. Using appropriate sports equipment can also reduce the risk of injury. Sports equipment refers to sport or activity-specific tools, such as balls, bats, sticks, and shoes. For the most benefit, protective equipment and gear should be:

1. The right equipment for the activity
2. Appropriately fitted
3. Appropriately maintained
4. Used consistently and correctly.

Be Active in Safe Environments

People can reduce their injury risks by paying attention to the places they choose to be active. To help themselves stay safe, people can look for:

• Physical separation from motor vehicles, such as sidewalks, walking paths, or bike lanes;
• Neighborhoods with traffic-calming measures that slow down traffic;
• Places to be active that are well-lighted, where other people are present, and that are well-maintained (no litter, broken windows);
• Shock-absorbing surfaces on playgrounds;
• Well-maintained playing fields and courts without holes or obstacles;
• Breakaway bases at baseball and softball fields; and
• Padded and anchored goals and goalposts at soccer and football fields.

Follow Rules and Policies That Promote Safety

Rules, policies, legislation, and laws are among the most effective and wide-reaching strategies for reducing activity-related injuries. These measures are designed to create safer environments and establish clear guidelines for minimizing risks during physical activities.

To benefit from these safeguards, individuals should actively seek out and follow applicable rules, policies, and laws. For instance:

• Helmet Use Policies: Wearing a bicycle helmet, as promoted by safety policies, significantly reduces the risk of head injuries for cyclists.
• Water Safety Rules: Adhering to swimming pool regulations, such as prohibitions against diving into shallow water, prevents head and neck injuries.
• Traffic Laws: Following pedestrian and cycling laws enhances safety when exercising or commuting in shared spaces like roads or trails.

By understanding and adhering to these policies, individuals can enjoy physical activity while minimizing risks to themselves and others.

For more on this topic, see the chapter on Unintentional Injuries, which explores how safety measures and proactive behaviors can prevent accidents in various settings.

Exercising in Weather and Low-Visibility Conditions

Exercising outdoors can be a rewarding experience, but weather and visibility conditions can present significant safety challenges. By taking a few precautions, you can stay safe while exercising in various environmental conditions, such as extreme temperatures, rain, wind, or low visibility at night or in fog.

Monitor Weather Conditions

Before heading out, check the weather forecast to anticipate adverse conditions, and adjust your plans accordingly.

• Heat and Humidity: In hot and humid weather, your risk of dehydration and heat stress increases. To stay safe:

  • Exercise during cooler hours, such as early morning or late evening.
  • Switch to indoor activities like swimming or use a gym when outdoor conditions are too extreme.
  • Lower the intensity of your workout to avoid overheating, opting for a brisk walk instead of a run.
  • Stay hydrated and take frequent breaks in the shade to rest and cool down.

• Cold Weather: Cold temperatures increase the risk of hypothermia and frostbite. To stay warm:

  • Dress in layers to trap body heat, and wear moisture-wicking clothing to keep sweat away from your skin.
  • Protect extremities by wearing gloves, hats, and thermal socks.
  • Warm up thoroughly before exercise to reduce the risk of muscle strains.

• Rain and Wind: Wet and windy conditions can make surfaces slippery, increasing the risk of falls.

  • Wear waterproof gear such as jackets and shoes with good grip to maintain traction on wet surfaces.
  • Avoid areas prone to flooding or downed trees during heavy rain and wind, and stay indoors during thunderstorms.
  • When your body becomes wet you lose heat more quickly, especially in cold rain. To prevent this, stay warm by wearing waterproof and moisture-wicking clothing.
  • Take shelter if conditions worsen.

Exercising in Low-Visibility Conditions

Exercising in the dark or low-visibility conditions, such as fog or rain, can be hazardous, particularly when navigating areas with traffic or uneven terrain.

• Wear High-Visibility or Reflective Clothing: Opt for bright colors or reflective gear (jackets, vests, shoes) to ensure you’re visible to drivers and other pedestrians. Consider illuminated accessories, such as LED lights or armbands, to further enhance visibility.

• Use Proper Lighting: Carry a flashlight or wear a headlamp to light your path, especially if you're running or walking in poorly lit areas. Bike lights are essential if you're cycling to make yourself visible to others.

• Choose Safe, Well-Lit Routes: Stick to routes that are well-lit and familiar. Avoid high-traffic areas or places with uneven terrain that may be harder to navigate in low light.

• Adjust for Weather-Related Reduced Visibility: In fog or rain, visibility is further compromised. Ensure your clothing and gear remain waterproof and windproof, and use reflective or brightly colored attire to stand out.

• Limit Distractions: In low-visibility conditions, it’s essential to stay alert. Avoid wearing headphones or anything that could distract you from your surroundings, such as vehicles or other potential hazards.

Stay Safe with These Extra Precautions

• Inform Someone: Always tell someone where you’re going and when you expect to return, especially if you're out in low-visibility conditions or extreme weather.
• Carry a Phone: Bring a fully charged phone for emergency situations.
• Monitor Your Health: If you're not used to exercising in these conditions, start slowly and gradually build up your endurance.

By being mindful of the weather and visibility factors, you can continue exercising safely throughout the year, no matter the conditions. Proper preparation and precautions go a long way in reducing risks, ensuring you stay active while minimizing injury.

Air Pollution and Exercise

Exposure to air pollution is associated with several adverse health outcomes, including asthma attacks and abnormal heart rhythms. If you live in an area with high pollution levels, you can reduce your exposure by modifying your exercise location or time. Exercise away from heavy traffic and industrial sites, especially during rush hour or times when pollution is known to be high. However, current evidence suggests that the benefits of being physically active, even in polluted air, outweigh the risks of being inactive. Regular exercise is important for overall health, and the risks of inactivity are often greater than the potential risks posed by air pollution.

When to Seek Medical Clearance

For individuals without diagnosed chronic conditions (such as diabetes, heart disease, or osteoarthritis) and who do not have symptoms (such as chest pain or pressure, dizziness, or joint pain), it is generally not necessary to consult a healthcare provider before increasing physical activity. Inactive people can usually begin moderate-intensity activities without risk, progressing gradually over time. Most individuals who start slowly and steadily increase their intensity are at very low risk for cardiovascular events or musculoskeletal injuries.

However, certain individuals may benefit from medical clearance, particularly those with existing chronic conditions or signs and symptoms. People with cardiovascular, metabolic, or renal diseases, respiratory disorders, or musculoskeletal conditions may need to consult their healthcare provider before beginning a new exercise regimen, especially if the intensity of exercise is moderate or vigorous.

If any of the following symptoms occur during or after exercise, it is crucial to stop exercising immediately and consult a healthcare provider:

• Chest pain or discomfort
• Shortness of breath
• Dizziness or fainting
• Heart palpitations or irregular heartbeats
• Severe joint pain or swelling
• Unusual fatigue or weakness

In conclusion, while physical activity is generally safe for most individuals, taking proper precautions can significantly reduce the risk of injury and adverse events. By gradually increasing activity, using appropriate protective gear, and exercising in safe environments, individuals can enjoy the numerous benefits of physical activity while minimizing potential risks. Remember that the key to a sustainable fitness routine is consistency, and with careful planning and attention to safety, physical activity can be a lifelong practice that promotes overall health and well-being.