By Madison Heitz
Injury Prevention & Ergonomic Specialist, Fit For Work
Key Insights
- Workplace design directly influences cardiac load, not only comfort or injury risk.
- Individual capacity (age, fitness, recovery) shapes how quickly job demands translate into strain.
- Small design and workflow changes can significantly reduce cumulative cardiac and physical stress over time.
Ergonomic design is often associated with comfort features, but in industrial environments it plays a far more critical role — shaping physical workload, influencing heart strain, and affecting long-term cardiovascular health. When jobs are designed without ergonomic principles in mind, they can require excessive force, sustained exertion, or inefficient movement patterns that elevate cardiovascular demand. Over time, this increased physiological strain may contribute not only to musculoskeletal injury, but to long-term cardiovascular health risks as well.
When work environments are designed without ergonomic principles in mind, they can increase physical effort, elevate heart strain, and contribute to long-term cardiovascular health risks.
Understanding Cardiac Load
Cardiac load is the physiological demand on the heart during activity or stress. It is commonly measured by heart rate or heart rate reserve (%HRR). Heart rate reserve is the difference between peak heart rate and resting heart rate. Peak heart rate is calculated by subtracting an individual’s age from 220, meaning maximum heart rate naturally declines with age. A normal resting heart rate is usually between 60-100 beats per minute, though it can be lower for very fit individuals.
Intensity is measured by the following percentages of HRR:
- Light: 30-40% HRR – This is the most common range for normal daily activities.
- Moderate: 40-65% HRR – If you’re still able to talk during an activity, the intensity likely falls in this range.
- High: 65+% HRR – Activity is so intense that talking is challenging.
This measurement system means that intensity of an activity is largely dependent on the individual’s heart rate reserve. Those with a lower HRR number, whether due to age, fitness level, or health, will reach higher percentages and intensity levels faster than someone with a greater HRR.
Risk Factors
Posture & Movement
Inefficient movements and awkward postures can raise heart rate and increase oxygen demand, even when the task doesn’t seem intense. Common examples include:
- Lifting repetitively with bad posture
- Reaching above shoulder or below hip height
- Twisting through the upper body
Even if the task may not seem visibly demanding, there can still be long-term effects. These movement patterns often result in greater fatigue and even dehydration as the body must expend more energy.
Prolonged periods of repetitive work without breaks further compound this effect. Over time, this cumulative strain can result in an elevated average heart rate and a reduced physiological ability to recover.
When performing moderate to high intensity activities, adequate rest periods are key. Return to anatomical neutral—a position where joints are naturally aligned and muscles operate with minimal strain—for 30-60 seconds every 30-60 minutes to reduce fatigue and physical stress on the body. These microbreaks give the cardiovascular system an opportunity to regulate and recover.
Intense Physical Demands
Roles with high physical demands, such as construction, cleaning, and industrial settings, spend a significant share—50% or more—of their workday at heart rate levels suggesting moderate cardiovascular effort. One study evaluating the impact of ergonomics on cardiovascular load during cleaning determined that cleaners adhering to good ergonomics principles demonstrated lower cardiac load compared to those not utilizing proper ergonomics.
Sedentary Work
Just as working at high intensity for long periods can be harmful, sedentary work with little movement can have a negative impact on health. This includes office workers who remain seated for long periods and other roles that require small, repetitive movements throughout the day. The cardiovascular system requires some aerobic exercise to maintain healthy function. Remaining stationary for prolonged periods can impair cardiac autonomic regulation and is associated with increased inflammation and metabolic dysfunction. Brief walks during microbreaks are an effective way for employees to add aerobic exercise to their day.
Stressors
Both environmental and workload stressors can activate the sympathetic nervous system and increase cardiac load. Common environmental stressors include:
- Noise: This is often addressed with headphones, earplugs, and behavioral controls to alert employees prior to sudden, loud noises.
- Vibration: Vibration is challenging to combat since the cause is often machinery, tools, or vehicles. When changing tools or adjusting workstation design is not an option, emphasizing ergonomics and biomechanics is the best solution.
- Temperature: Ensure extremes in temperature are managed or mitigated through environmental controls and appropriate attire.
Work stressors like tight deadlines and high pressure also contribute to greater cardiac load. Establishing a sustainable work pace and improving organization of the work environment are effective adjustments to manage cardiac stress.
Age
Maximum heart rate tends to decrease with age due to changes in the heart’s natural pacemaker. The calculation of peak heart rate requires subtracting age from 220, so an older individual will have a lower maximum heart rate. This means that they will reach their maximum more quickly, and it may take longer for their heart to return to its resting rate. Overall fitness level tends to decrease with age as well, elevating the risk of exertion fatigue during high-intensity activity.
Warning Signs
It is very important to maintain awareness of indications that the cardiovascular system is under too much strain. Typical signs include:
- Unusually severe fatigue during or after work
- Notably high heart rate during light or moderate tasks
- Shortness of breath
- An elevated resting heart rate, even after shift completion
While recovery time varies for everyone, if a team member notices these issues, ergonomic evaluation and intervention are recommended. Employees should reach out to their onsite providers and safety team for further evaluation and guidance.
Implementing Ergonomics to Reduce Cardiac Load
Process improvements are the first step to implementing an effective ergonomics program. Engineering controls — changes to tools, workstation layout, flow, and task height — are the most impactful ways to reduce unnecessary physical demand. Adjusting workstation design and tools to achieve neutral anatomical positions can provide marked improvement in employee comfort and reduced cardiac load.
Optimizing biomechanics is the next step toward reducing cardiac load. Ergonomics professionals play a key role in assessing existing workflows by observing and engaging with employees. A relationship-building, conversation-based approach establishes open communication with employees, creating a receptive environment for training and addressing concerns.
Teaching employees how to maintain neutral postures, move efficiently, and minimize unnecessary exertion further reduces cumulative cardiac load. Establishing good ergonomic practices during the onboarding process helps establish strong movement habits early, supporting long-term employee well-being and success.
When physical demands cannot be engineered out entirely, administrative strategies can help manage cumulative strain. Microbreaks and job rotations are effective tools to combat fatigue and overexertion from repetitive movements. In more sedentary roles, prioritize aerobic movement during microbreaks to promote circulation and reduce potential static postures issues.
The combination of engineering controls, optimized biomechanics, and administrative practices creates a thoughtful, comprehensive approach to reducing cardiac load.
Small Changes Can Have a Big Impact
At one of our sites, employees were required to evaluate food products and discard those that did not meet quality standards. The discard process involved twisting through the torso and tossing the product behind them which introduced unnecessary strain and increased ergonomic risk.
An ergonomic assessment identified this task as an opportunity for improvement. A simple design change was recommended: installing a moving line along the wall so discarded product could be placed directly in front of the employee. This adjustment eliminated the need for a full‑body twist and replaced it with a short, forward arm movement, thus reducing physical demand on the employees.
After installing the moving line, the employer reported noticeable improvements in employee comfort and overall satisfaction.
Conclusion
Ergonomics principles have a major impact on more than the musculoskeletal system—they also contribute to improved long-term cardiovascular health. Implementing an ergonomics program is an investment that benefits businesses through fewer reportable and lost-time incidents while also having a positive impact on employee well-being and satisfaction.
Interested in Making Small Changes That Add Up?
Thoughtful design and simple adjustments can make a meaningful difference. Connect with our team to learn how ergonomic insights can support your workforce.
Madison Heitz is an Injury Prevention and Ergonomic Specialist with Fit For Work, based in Washington. Since joining the company in 2024, she has been an active contributor not only in her onsite role but also through her involvement with the Verified Influencer Program, the onboarding team, and as a member of the FFW Institute, where she helps create educational resources to support employee engagement.
Madison earned her bachelor’s degree in athletic training from Marist College in 2021. She is passionate about healthcare, building strong relationships, preventing workplace injuries, and fostering best practices to create safer, healthier, and more productive work environments.
