Cardiac Output: 10 Actionable Insights for Unlocking Peak Performance

What is Cardiac Output?

Cardiac output refers to the amount of blood the heart pumps out per minute.

This vital metric gives us a sense of how well the heart is functioning as a pump.

The average cardiac output for an adult at rest is about 5 liters per minute, but this can increase significantly during physical exertion.

How to Calculate Cardiac Output?

Cardiac output (CO) is calculated using the formula: CO = Heart Rate (HR) x Stroke Volume (SV), where heart rate is the number of heartbeats per minute, and stroke volume is the amount of blood pumped out with each beat.

How Does Positive Pressure Ventilation Affect Cardiac Output?

Positive pressure ventilation can impact cardiac output in several ways.

It increases pressure in the chest cavity, thereby decreasing venous return (the amount of blood returning to the heart).

This reduces preload (the volume of blood in the heart at the end of filling) and thus may decrease cardiac output.

In some cases, it can also increase afterload (the resistance the heart must overcome to pump blood), further reducing cardiac output.

What is a Normal Cardiac Output?

A normal cardiac output at rest for a healthy adult varies between 4 to 8 liters per minute.

This figure can fluctuate based on various factors, including age, gender, body size, metabolic rate, and physical activity level.

Which of the Following Would Increase Cardiac Output?

Several factors can increase cardiac output.

Physical exercise is a primary driver, causing both heart rate and stroke volume to increase.

Other factors that could potentially increase cardiac output include sympathetic nervous system stimulation, medications such as dobutamine, increased body temperature, and some medical conditions, such as hyperthyroidism.

How to Measure Cardiac Output?

There are various methods to measure cardiac output, such as the Fick principle, thermodilution, pulse contour analysis, Doppler echocardiography, and cardiac magnetic resonance imaging (MRI).

These methods can vary in accuracy, invasiveness, and practicality.

Genetics of Cardiac Output

Genetics and Heart Structure

There are multiple genes that contribute to the development and function of the heart.

Genetic variations or mutations in these genes, such as those encoding for proteins that make up the heart muscle (myosin, actin, etc.), can lead to conditions like hypertrophic cardiomyopathy or dilated cardiomyopathy, which can decrease cardiac output.

Indirect Genetic Influences on Cardiac Output

In addition to genes that directly influence heart structure and function, there are also genetic factors that can indirectly affect cardiac output.

For example, genetic variations that regulate blood pressure, lung function, or blood volume can influence afterload and preload, key factors in determining cardiac output.

Genetics of Elite Athletes: High Cardiac Output and Performance

An intriguing area of research is studying “elite genes” or gene variants that confer superior athletic performance, including high cardiac output.

Specific examples include variations in the ACE gene, associated with greater endurance performance.

Which ACE gene variants do you have? Check your Ancestry DNA, 23andMe raw data

Further, the ACTN3 gene is linked to superior performance during short, intense bursts of activity.

Which ACTN3 gene variants do you have? Check your Ancestry DNA, 23andMe raw data

The Interplay of Genetics and Lifestyle

While genetics plays a significant role in cardiac output, lifestyle factors, including diet and exercise, are equally important.

They can help to manage or even overcome some genetic predispositions, offering avenues to optimize cardiac output and overall heart health.

The Future of Genetics and Cardiac Output

Our growing understanding of the genetics of cardiac output opens up potential future applications.

Genetic testing can be used to predict risk for certain cardiovascular diseases, identify individuals who may benefit from specific types of training or interventions, or even tailor treatments based on individual genetic makeup.

However, more research is needed to bring these promising possibilities into reality.

While the specific role of each Single Nucleotide Polymorphism (SNP) in cardiac output has not been fully defined, certain SNPs have been associated with traits that could influence cardiac output.

Here is an illustrative table of a few examples:

SNP ID	Gene Name	Associated Trait
rs699	AGT (Angiotensinogen)	Hypertension, impacts afterload
rs4340	ACE (Angiotensin I Converting Enzyme)	Alters blood pressure and electrolyte balance, linked with endurance performance
rs1815739	ACTN3 (Actinin Alpha 3)	Muscle function, associated with sprint performance
rs1800795	IL6 (Interleukin 6)	Chronic heart failure, impacts inflammatory response
rs5186	ADRB1 (Adrenoceptor Beta 1)	Response to beta-blocker therapy in heart failure

How Does Cardiac Output Affect Your Workouts?

Cardiac output has a direct impact on your workouts.

Higher cardiac output means your heart can pump more blood, supplying your muscles with more oxygen and nutrients, leading to better performance and endurance.

How Does Cardiac Output Affect Sports Performance?

Cardiac output – the volume of blood that the heart pumps per minute – plays a crucial role in sports performance.

A higher cardiac output means more oxygen is delivered to the muscles, which can improve endurance and performance.

Impact of Genetic Variants on Cardiac Output and Sports Performance

Certain genetic variants can impact factors related to cardiac output and, consequently, sports performance.

Here are a few examples:

ACE Gene (Angiotensin I Converting Enzyme)

The ACE gene can influence endurance performance.

One variant of the ACE gene, the I variant, is associated with greater endurance performance, potentially due to its effect on the cardiovascular system.

Fitness Tip: To compensate for not having the I variant, training strategies can focus on improving cardiorespiratory endurance, like long-distance running or cycling.

ACTN3 Gene (Actinin Alpha 3)

The ACTN3 gene influences muscle function.

The XX variant, which results in a deficiency of the alpha-actinin-3 protein, is associated with better endurance performance.

Fitness Tip: If you have the RR or RX variant instead, incorporating endurance training can be beneficial.

ADRB1 and ADRB2 Genes (Beta-1 and Beta-2 Adrenergic Receptors)

These genes can affect heart rate and the force of heart contraction.

Variants that result in an increased heart rate might enhance performance in short-duration, high-intensity sports.

Fitness Tip: For individuals with variants that lead to a slower heart rate response, training that focuses on high-intensity interval training (HIIT) might be beneficial to stimulate heart rate and increase cardiac output.

Which ADRB1 & ADRB2 gene variants do you have? Check your Ancestry DNA, 23andMe raw data

NOS3 Gene (Nitric Oxide Synthase 3)

The NOS3 gene influences the production of nitric oxide, a molecule that helps dilate blood vessels and increase blood flow.

Variants that reduce nitric oxide production may impact cardiac output and sports performance.

Fitness Tip: For individuals with such variants, consuming a diet rich in nitrates – found in beetroot or leafy green vegetables – can boost nitric oxide levels in the body.

Which NOS3 gene variants do you have? Check your Ancestry DNA, 23andMe raw data

Exercises to Improve Cardiac Output

Aerobic Exercises

Aerobic exercises, also known as cardio, are one of the most effective ways to increase cardiac output over time.

These exercises increase your heart rate and breathing, improving cardiovascular fitness. Some effective aerobic exercises include:

1. Running or Jogging: Regular running or jogging can significantly improve your heart’s efficiency and increase cardiac output. Start slow and gradually increase your speed and distance as your fitness improves.
2. Cycling: Whether outdoor or indoor, cycling is a low-impact exercise that can effectively increase your heart rate and cardiac output.
3. Swimming: Swimming is a total body workout that is particularly effective for increasing cardiac output. The water’s resistance ensures that your body works harder, leading to an increase in heart rate.

High-Intensity Interval Training (HIIT)

High-Intensity Interval Training involves short bursts of intense exercise followed by short periods of rest.

This form of exercise can lead to significant improvements in cardiovascular health, including increased cardiac output.

A simple way to start HIIT might be sprinting for 30 seconds, then walking for a minute, and repeating this pattern for 20-30 minutes.

Strength Training

While typically associated with muscle building, strength training can also contribute to improving cardiac output.

Lifting weights increases heart rate during exercise and requires the heart to pump more blood to the working muscles.

It’s important to start with weights you can handle and gradually increase them as your strength improves.

Yoga and Pilates

While yoga and Pilates may not immediately come to mind when thinking about increasing cardiac output, these exercises can contribute to a stronger cardiovascular system.

They improve lung capacity, blood flow, and heart health, indirectly improving cardiac output.

Balancing Exercise and Rest

While exercise is important, rest is equally vital.

Overtraining can lead to decreases in cardiac output as the heart is not given sufficient time to recover.

Ensure you have a balanced workout routine with adequate rest periods to allow your body to recuperate and adapt.

Consult with a healthcare or fitness professional before starting any new exercise regimen.

They can provide guidance on how to safely and effectively improve your cardiac output based on your current fitness level and health status.

Cardiac Output: Eating for Your Genes

Examples of genes that may influence factors related to cardiac output and how dietary changes can help to manage these influences.

ACE Gene (Angiotensin I Converting Enzyme)

The ACE gene influences blood pressure, a factor that affects cardiac output. Variations in this gene can lead to differences in blood pressure regulation.

Diet Tip: For individuals with genetic variants that lead to higher blood pressure, adopting a low-sodium diet can help manage this condition.

APOB Gene (Apolipoprotein B)

The APOB gene affects LDL cholesterol levels. High LDL cholesterol can lead to atherosclerosis, which can impair heart function and reduce cardiac output.

Diet Tip: For individuals with genetic variants that predispose them to higher LDL cholesterol levels, a diet low in saturated and trans fats can help manage cholesterol levels.

AGT Gene (Angiotensinogen)

The AGT gene can also influence blood pressure.

Diet Tip: For individuals with genetic variants that predispose them to hypertension, following the DASH (Dietary Approaches to Stop Hypertension) diet, which is rich in fruits, vegetables, whole grains, and low-fat dairy products, can be beneficial.

ACTN3 Gene (Actinin Alpha 3)

The ACTN3 gene affects muscle function, including the muscles of the heart.

Diet Tip: While diet may not directly influence this gene’s effects on the heart muscle, consuming a well-rounded diet with plenty of lean proteins can support overall muscle health.

MTHFR Gene (Methylenetetrahydrofolate Reductase)

The MTHFR gene affects levels of homocysteine, an amino acid that at high levels can increase the risk of heart disease.

Diet Tip: For individuals with a variant of this gene that leads to higher homocysteine levels, a diet rich in B vitamins, particularly folate, can help manage homocysteine levels.

Folate-rich foods include leafy green vegetables, fortified grains, and legumes.

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