Cardiovascular Training

Walking regularly helps improve heart health and build cardiovascular endurance. Image Credit: RHN Team Picture Bank

What is Cardiovascular Training?

Regular physical activity is essential for improving overall health and managing or preventing chronic conditions. Cardiovascular training, otherwise known as cardio or aerobic training, involves exercises that raise your heart rate and improve the efficiency of your heart, lungs, and respiratory system. Cardiovascular training can include activities like walking, jogging, cycling, swimming, dancing, and many more activities that raise your heart rate for extended periods of time while using large muscle groups in a rhythmic manner. Cardio has numerous benefits for the cardiorespiratory system that support a longer, healthier life and the ability to perform daily activities with better ease as you age. Despite the known benefits, according to the Centers for Disease Control and Prevention, only 47.2% of Americans met the Physical Activity Guidelines for Americans recommendations for cardio activity in 2024. This means many Americans, about half of the population, are not getting enough cardio activity to experience health benefits.

Benefits of Cardiovascular Training

1. Improved cardiovascular functioning

• Regular cardiovascular activity strengthens the heart muscle, allowing it to pump more blood with each beat, a change known as increased stroke volume. As stroke volume increases, resting heart rate often decreases because the heart can circulate blood more efficiently. Cardio training also improves the elasticity and function of blood vessels, supporting healthy blood pressure regulation. Over time, these adaptations improve overall cardiac output and reduce strain on the cardiovascular system.

2. Improved respiratory functioning and oxygen transport

• Aerobic exercise improves the efficiency of the respiratory system by enhancing the lungs’ ability to exchange oxygen and carbon dioxide. It also increases capillary (tiny blood vessels that connect arteries and veins) density in working muscles, allowing more oxygen-rich blood to reach tissues. In addition, cardio training increases mitochondrial density, meaning the number of mitochondria (specialized structures inside cells that produce energy) increases within muscle cells. Mitochondria use oxygen to convert nutrients into ATP (adenosine triphosphate), the body’s primary energy molecule that powers muscle contraction and other cellular processes. As these energy-producing structures become more numerous and efficient, muscles are better able to use oxygen to generate energy, which often results in improved endurance and less shortness of breath during daily activities.

3. Weight management

• During aerobic activity, muscles require energy and use a combination of glucose and fatty acids as fuel. Consistency with cardiovascular training increases the body’s total energy expenditure and can support a healthy body weight when combined with appropriate nutrition. Regular aerobic exercise also improves insulin sensitivity, helping the body regulate blood glucose (blood sugar) more effectively. These metabolic adaptations contribute to long-term weight management and reduced risk of excess body fat accumulation.

4. Improved circulation and brain health

• Aerobic exercise improves endothelial (thin layer of specialized cells that line the inside of blood vessels) function, which enhances the ability of blood vessels to dilate and deliver blood efficiently throughout the body, including to the brain. Increased cerebral blood flow supports oxygen and nutrient delivery to brain tissue. Research shows that regular aerobic activity is associated with improved cognitive function and a reduced risk of stroke and neurodegenerative conditions such as dementia. Exercise may also stimulate the release of brain-derived neurotrophic factor (BDNF), a protein that supports neuron (nerve cell that sends signals to the body) growth and maintenance.

5. Improved joint stability

• Regular cardio movement promotes circulation of synovial fluid within joints, which helps lubricate cartilage, reduce friction during movement, absorb shock, and reduce stiffness. Aerobic activity also strengthens the muscles surrounding joints, providing greater stability and shock absorption. Consistent movement through a comfortable range of motion can help maintain flexibility and reduce discomfort associated with inactivity or certain chronic conditions. These adaptations support functional movement and joint health across the lifespan.

6. Improved sleep

• Moderate aerobic exercise has been shown to improve sleep quality and duration in many adults. Physical activity helps regulate circadian rhythms (the body’s 24-hour internal clock) and may reduce symptoms of anxiety that interfere with falling asleep. Exercise also promotes healthy metabolic function, which can support stable blood glucose levels overnight. Engaging in regular cardio activity is associated with falling asleep more easily and experiencing deeper stages of sleep.

7. Improved muscular endurance

• Aerobic training increases mitochondrial density and capillary networks within skeletal muscle, allowing muscles to sustain activity for longer periods. These adaptations improve the muscles’ ability to produce energy efficiently using oxygen, a process known as aerobic respiration. Activities such as brisk walking, cycling, or uphill movement can strengthen and increase endurance in the muscles most involved in the activity. Improved muscular endurance supports daily tasks and reduces fatigue during prolonged movement.

8. Enhanced mental health

• Aerobic exercise stimulates the release of neurotransmitters (chemical messengers between nerve cells) and neurochemicals (brain chemicals affecting mood and behavior) such as endorphins, serotonin, and dopamine, which are associated with improved mood. Regular physical activity is linked to reduced symptoms of depression and anxiety. Exercise also lowers levels of stress hormones such as cortisol over time. These physiological responses contribute to improved emotional regulation and overall psychological well-being.

9. Reduced risk of chronic disease

• Regular aerobic activity is associated with a lower risk of cardiovascular disease, type 2 diabetes, stroke, and certain cancers. Exercise improves insulin sensitivity (blood glucose regulation), blood lipid (fat) profiles, and blood pressure regulation. It also reduces systemic inflammation, which plays a role in many chronic diseases. Meeting recommended aerobic activity levels is strongly linked to increased longevity and reduced all-cause mortality risk.

10. Increased energy levels

• Although exercise requires energy, regular aerobic training improves the body’s ability to produce and use energy efficiently. Increased mitochondrial density enhances ATP production within muscle cells through aerobic respiration. Improved cardiovascular and respiratory efficiency allows oxygen to be delivered more effectively to tissues. Over time, these adaptations often result in increased energy availability and reduced fatigue during daily activities.

Recommendations for Cardio Training

Physical Activity Guidelines

The Physical Activity Guidelines for Americans recommend that adults get at least:

• 150 minutes of moderate-intensity cardiovascular exercise per week OR
• 75 minutes of vigorous-intensity cardiovascular exercise per week OR
• A combination of both moderate-intensity and vigorous-intensity cardiovascular exercise per week

These recommendations can be broken down to about 30 minutes of cardio activity, 5 days a week or about 21 minutes of cardio activity per day to meet the minimum requirements. For greater health benefits, 300 minutes per week of moderate-intensity cardio activity is recommended.

How to Measure Exercise Intensity: The Talk Test

Using the talk test helps you know if you are exercising at the right intensity. The talk test is a simple, research-supported method to estimate exercise intensity without equipment.

• Low intensity: You can sing during the activity.
• Moderate intensity: You cannot sing, but you can talk during the activity.
• Vigorous intensity: You cannot sing or talk during the activity.

Choosing the Right Environment for Cardio

Exercising Outdoors

Exercising outdoors not only supports physical activity goals, but time spent in nature is also associated with additional mental health benefits. However, in extreme heat or cold, the body may have difficulty regulating its temperature, increasing the risk of heat exhaustion, heat stroke, frostbite, or hypothermia.

To avoid negative effects of extreme heat:

• Stay hydrated before, during, and after exercise.
• Wear light, breathable clothing. Lightweight, moisture-wicking fabrics are recommended.
• Stop exercising if you feel nausea or dizziness, experience trouble breathing, or are unable to sweat.

To avoid negative effects of extreme cold:

• Dress in layers and wear breathable clothing. Stay dry and watch wind chill levels.
• Use appropriate footwear with good traction to reduce slip risk on icy or wet surfaces.
• Stay hydrated as cold temperatures can cause dehydration.

Finally, be mindful of air quality, especially if you have breathing issues. If allergy season makes outdoor exercise difficult, talk to your healthcare provider about options to reduce your discomfort.

Exercising Indoors

Exercising indoors can be a convenient option for achieving the recommendations for cardio training. Indoor walking options, such as malls or fitness center tracks, provide safe, climate-controlled alternatives during extreme weather. Simply walking around the house, dancing to your favorite music, or going up and down stairs at the office can contribute to your total cardio activity for the week. All cardio activity, even in small bouts, counts towards the recommended totals.

Choose Cardio you Enjoy and Incorporate Small Changes

The best type of cardio is what you actually enjoy doing and will do regularly long-term. If running is not your thing, try swimming, dancing, biking, pickleball, or other activities. Keep trying one new activity at a time until you find something you enjoy. This will help you stay consistent with your cardio goals and make the task of reaching the 150 recommended minutes feel like less of a burden. You can also make small lifestyle changes to support your cardio goals. Consider staying active throughout your day to reduce sedentary behavior like breaking up sitting sessions by moving every 30 minutes to 1 hour with low-intensity activities like walking. Other helpful tips include parking further away in the parking lot to increase the amount you have to walk, taking the stairs instead of the elevator, and starting more active hobbies like gardening or hiking.

Cardio Training Safety Considerations for Special Populations

Asthma

Regular aerobic exercise can improve cardiorespiratory fitness and may enhance overall lung efficiency and quality of life in individuals with asthma. With appropriate management, many individuals with asthma can safely participate in moderate-intensity aerobic activity.

Why caution is needed:
Exercise can sometimes make the airways in your lungs tighten, especially if the air is cold, dry, or full of pollen. Starting exercise too fast without warming up can make this more likely.

Safety considerations:

• Use prescribed quick-relief (rescue) inhalers as directed before exercise if recommended by a healthcare provider.
• Incorporate a gradual 5–10 minute warm-up to reduce likelihood of airway complications.
• Choose steady, moderate-intensity activity rather than sudden high-intensity bursts to reduce symptom risk.
• Avoid exercising in cold, dry air or high-allergen conditions when possible.
• Stop activity if experiencing wheezing, chest tightness, severe shortness of breath, or dizziness.

Healthcare provider reminder:
Individuals with asthma should review their asthma action plan with their healthcare provider before beginning a new cardio routine to ensure medications and management strategies are optimized.

Diabetes

Aerobic exercise improves blood glucose regulation by increasing glucose uptake into working muscles through both insulin-dependent and insulin-independent pathways. Insulin, a hormone that helps move glucose from the blood into cells for energy, becomes more effective with regular cardio activity, especially in individuals with type 2 diabetes. It is also associated with improved A1C levels, cardiovascular health, and reduced risk of diabetes-related complications.

Why caution is needed:
Because exercise lowers blood glucose, individuals using insulin or certain glucose-lowering medications may be at risk for hypoglycemia (low blood glucose levels). Conversely, very high blood glucose levels (particularly above 250 mg/dL with ketones present) may increase risk for complications during exercise.

Safety considerations:

• Check blood glucose before exercise. For many individuals, a pre-exercise range of approximately 100–250 mg/dL is considered safe, unless otherwise directed by a healthcare provider.
• If blood glucose is below recommended levels, follow the Rule of 15: consume 15 grams of rapid-acting carbohydrate and recheck levels before continuing with activity to ensure blood glucose is within the safe range.
• Monitor glucose before, during, and after prolonged or higher-intensity cardio exercise to understand individual responses.
• Schedule exercise in consideration of meals and medication timing to reduce hypoglycemia risk.
• Inspect feet daily and especially after exercise. Wear properly fitted footwear to reduce risk of injury; this is particularly important for individuals with neuropathy.

Healthcare provider reminder:
Individuals with diabetes should consult their healthcare provider before beginning or significantly increasing aerobic activity, especially if complications such as neuropathy, retinopathy, or cardiovascular disease are present.

Hypertension (High Blood Pressure)

Regular aerobic exercise is associated with reductions in resting systolic (pressure during heartbeats) and diastolic (pressure between heartbeats) blood pressure, often by approximately 5–8 mmHg in individuals with hypertension. Cardio also helps your blood vessels work better, stay flexible, and improves your cholesterol levels by increasing “good” cholesterol (HDL). These adaptations reduce overall cardiovascular risk.

Why caution is needed:
Individuals with uncontrolled hypertension or underlying cardiovascular disease may be at increased risk during high-intensity exertion. Sudden spikes in blood pressure can occur with abrupt or vigorous activity.

Safety considerations:

• Begin with light to moderate intensity aerobic activity and gradually increase duration and intensity over time.
• Avoid sudden, maximal-effort exertion, especially if previously sedentary.
• Avoid positions or exercises where your head is lower than your heart, as this can temporarily increase blood pressure and place extra strain on blood vessels.
• Exercise in climate-controlled environments during extreme heat, as high temperatures may increase cardiovascular strain.
• Stop exercise immediately if experiencing chest pain, unusual shortness of breath, dizziness, or palpitations (noticeable or rapid heartbeats), and seek medical attention if symptoms persist.

Healthcare provider reminder:
Individuals with hypertension should consult their healthcare provider before starting an exercise program to determine appropriate intensity levels and ensure blood pressure is adequately controlled. Check blood pressure regularly if advised by your provider.

Physical Limitations

Aerobic exercise helps your heart and lungs work better, builds muscle endurance, improves blood flow, and makes everyday activities easier, even when performed from a seated position or with modifications. Studies show that adapted aerobic exercise can improve fitness, balance, and overall quality of life for people with limited mobility.

Why caution is needed:
Mobility impairments, balance deficits, joint instability, or chronic pain conditions may increase fall risk or injury during traditional cardio weight-bearing activities, such as walking or dancing.

Choose activities that match your ability level, such as seated cardio, water-based exercise, or low-impact options like cycling or elliptical machines. Use stable support (e.g., wall, rail, or sturdy chair) if you need help with balance. Start slow and gradually increase intensity to help your body safely adjust. Stop activity if you feel significant joint pain, instability, or dizziness. Wear supportive footwear and exercise in a safe, clutter-free space to reduce fall risk.

Safety considerations:

• Choose activities that match your current ability level, such as seated cardio, water-based exercise, or low-impact options like cycling or elliptical machines.
• Use stable support (e.g., wall, rail, sturdy chair, bench) if you need assistance with balance.
• Start slow and gradually increase intensity to help your body safely adjust and allow neuromuscular (brain/muscle) adaptation.
• Stop activity if experiencing significant joint pain, instability, or dizziness.
• Wear supportive footwear and exercise in a safe, clutter-free space to reduce fall risk.

Healthcare provider reminder:
Individuals with significant mobility limitations, neurological conditions, osteoporosis, or recent surgery should consult their healthcare provider or a qualified exercise professional before beginning a cardio program.

Getting Started with Cardiovascular Exercise

Research shows that gradual, consistent participation in aerobic activity leads to measurable improvements in cardiovascular fitness, metabolic health, and overall well-being. Establishing a routine and progressing safely over time supports long-term adherence and reduces risk of injury.

• Start Slowly and Progress Gradually: Aerobic fitness improves through progressive overload, meaning your body adapts as you slowly increase how hard or how long you exercise over time. Individuals who are new to exercise or returning after a period of inactivity should begin with low-intensity activities and shorter durations, then gradually increase frequency, duration, and intensity as tolerated. This gradual progression allows the cardiovascular system and musculoskeletal system (muscles, joints, and connective tissues) to adapt safely. Sudden increases in intensity or duration may increase the risk of excessive fatigue, dizziness, or musculoskeletal injury.

• Stay Hydrated: Adequate hydration supports temperature regulation, cardiovascular function, and normal kidney function during exercise. Fluid losses increase with sweating, particularly during prolonged or higher-intensity activity or in hot environments. Dehydration can impair physical performance, increase heart rate, and contribute to fatigue or lightheadedness. General daily fluid intake recommendations are approximately 15.5 cups for men and 11.5 cups for women from all beverages and foods combined, though individual needs vary based on body size, climate, altitude, and activity level. Drinking fluids before, during, and after exercise helps maintain fluid balance. Talk with your healthcare provider about hydration recommendations specific to your body and health conditions.

• Include a Warm-up and Cool-down: A proper warm-up gradually increases heart rate, breathing rate, and blood flow to working muscles. Performing 5–10 minutes of lower-intensity movement before aerobic exercise prepares the cardiovascular and musculoskeletal systems for increased workload and may reduce injury risk. A cool-down of similar duration allows heart rate and blood pressure to return to resting levels more gradually. For example, if you plan to run for 20 minutes, walk at a light pace or slow jog for 5 minutes directly before and after the run. Gradual transitions into and out of exercise are especially important for individuals with cardiovascular or metabolic conditions.

• Choose Activities You Enjoy and Can Maintain: Long-term adherence to physical activity is strongly associated with perceived enjoyment and personal relevance. Selecting aerobic activities that align with individual preferences, abilities, and lifestyle increases the likelihood of consistent participation. Social support, such as exercising with a partner or group, is also associated with improved exercise adherence. Consistency over time is a key factor in achieving and maintaining the health benefits of cardiovascular training.

Programs to Support Your Physical Activity

The Clemson Extension Rural Health and Nutrition Team offers free, evidence-based physical activity programs designed to meet participants where they are and provide support every step of the way. Whether you want to build a walking routine with WalkSC, create a balanced movement plan through MoveSC, improve strength and function with Practical Strength, or explore gentle balance and flexibility training through Yoga for Every Body, our programs provide structured guidance, education, and ongoing support from trained fitness and health coaches. Designed for beginners and experienced movers alike, these programs focus on building confidence, consistency, and realistic habits that support long-term health.

Learn more about our physical activity programs and additional resources by visiting the Rural Health and Nutrition Team Website or contacting the Rural Health and Nutrition Team via email at healthextension@clemson.edu.

For additional information on safe and effective physical activity and nutrition strategies to support physical activity, review our fact sheets on Strength Training and Nutrition to Support Physical Activity.

References:

• American Diabetes Association. (2019). Physical activity/exercise and diabetes: A position statement of the American Diabetes Association. Diabetes Care, 42(Suppl 1), S79–S85. https://doi.org/10.2337/dc19‑S008
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• Centers for Disease Control and Prevention. (2023). Exercise — fast stats. https://www.cdc.gov/nchs/fastats/exercise.htm
• Cleveland Clinic. (2024). Heart risks associated with extreme exercise. https://health.clevelandclinic.org/can-too-much-extreme-exercise-damage-your-heart
• Colberg, S. R., Sigal, R. J., Fernhall, B., Regensteiner, J. G., Blissmer, B. J., Rubin, R. R., … & Braun, B. (2016). Exercise and type 2 diabetes: The American College of Sports Medicine and the American Diabetes Association: Joint position statement. Diabetes Care, 39(11), 2065–2079. https://doi.org/10.2337/dc16‑1728
• Harvard Health. (2023). The importance of exercise when you have diabetes. https://www.health.harvard.edu/staying‑healthy/the‑importance‑of‑exercise‑when‑you‑have‑diabetes
• Harvard Health Publishing. (2025). How much water should you drink? Harvard Health. https://www.health.harvard.edu/staying-healthy/how-much-water-should-you-drink
• Kidney UK (National Kidney Federation). (2020). Can I safely exercise with high blood pressure (hypertension)? https://www.kidney.org.uk/can‑i‑safely‑exercise‑with‑high‑blood‑pressure
• Lohmeyer, S. (2023). How to exercise safely in the heat. NPR. https://www.npr.org/sections/health‑shots/2021/07/19/1016989389/how‑to‑heat‑proof‑your‑summer‑workout
• Mayo Foundation for Medical Education and Research. (2022). Exercise‑induced asthma. Mayo Clinic. https://www.mayoclinic.org/diseases‑conditions/exercise‑induced‑asthma/symptoms‑causes/syc‑20372300
• Mayo Foundation for Medical Education and Research. (2024). Diabetes and exercise: When to monitor your blood sugar. Mayo Clinic. https://www.mayoclinic.org/diseases‑conditions/diabetes/in‑depth/diabetes‑and‑exercise/art‑20045697
• Shelton, S. (2024). Water vs. sports drinks: What’s better for hydrating in the heat? https://blog.prismahealth.org/water‑vs‑sports‑drinks‑whats‑better‑for‑hydrating‑in‑the‑heat/
• Texas Heart Institute. (2025). Stay heart‑smart in the heat: Summer tips to prevent heat‑related illness. https://www.texasheart.org/heart‑health/heart‑information‑center/topics/hot‑weather‑exercise‑tips/
• U.S. Department of Health and Human Services. (2018). Physical Activity Guidelines for Americans. 2nd ed. Washington, DC.

Authors:

• Camden Bryan, Rural Health and Nutrition Extension Agent, Statewide
• Ellie Lane, Extension Associate, Rural Health and Nutrition

Reviewed by:

• Melissa Bales, Extension Associate, Rural Health and Nutrition