Though pharmaceutical approaches for treating atherosclerotic cardiovascular disease (ASCVD) have experienced rapid growth, rightfully garnering a great deal of attention and publicity, lifestyle intervention remains the primary component of any cardiovascular wellness strategy. While what constitutes a "lifestyle intervention" can vary widely, the key tenets of any strategy rest on regular physical activity and healthy nutritional choices.^1,2 While cardiovascular guidelines around the world are largely similar in many of their recommendations on physical activity and nutrition, there are also key differences and areas of variation.³ The aim of this piece is to highlight common features for clinical practice, as well as key differences for further consideration between the major United States (US) and European cardiovascular prevention guidelines on physical activity and nutrition.

Physical Activity

Increased physical activity remains one of the top drivers in improving cardiovascular health, as well as providing for a wide variety of benefits outside of the cardiovascular system.^4,5 Studies on exercise and physical fitness have consistently exhibited reductions in downstream cardiovascular events, a benefit which continues largely without limit alongside increasing amounts of physical activity attained.⁶ As a result, these benefits have been reflected across US and European cardiovascular guidelines and incorporated into recommendations for clinicians and patients.

Within the US, guideline organizations have been very consistent in their messaging with respect to degrees, or preferred lower limits, of physical activity for most patients. The Department of Health and Human Services 2018 physical activity guidelines and the 2019 American College of Cardiology (ACC)/American Heart Association (AHA) primary prevention guideline are similar in recommending a minimum of 150 minutes of moderate-intensity (3.0-5.9 metabolic equivalents, such as biking, walking quickly, swimming) activity, respectively, or at least 75 minutes of strenuous (≥6 metabolic equivalents, such as jogging, and most recreational sports) physical activity (Class I recommendation). This recommendation is compatible with the 2017 ACC/AHA hypertension guideline, which notes an inverse relationship between physical fitness and blood pressure.⁷

The same physical activity levels are recommended for patients with type 2 diabetes by the US and European guidelines to reduce ASCVD risk, improve glycemic control, and help with weight loss. While there is no upper limit on the benefits received from regular brisk physical activity, there is also no lower limit at which benefits begin accruing. Thus, where each guideline might recommend a preferred minimum of 150 minutes per week of moderate-intensity physical activity, any amount of physical activity above baseline is beneficial in reducing the risk of cardiovascular events (Class IIa recommendation).

The US guidelines go even further, specifically calling for a reduction in sedentary behavior – defined as <1.5 metabolic equivalents while awake, such as standing or sitting at a desk – which can be mitigated by increasing physical activity at other times of the day.⁸ In a change from the first edition, the second edition 2018 physical activity guidelines no longer recommend any interval lengths of physical activity at one time, or required "bouts" of exercise, to reach the 75 minute/150 minute thresholds, and suggest that any sum of activities leading to the recommended amounts per week should be considered sufficient.⁹ Lastly, there is significant emphasis on the importance of counseling patients regularly on their physical activity levels and how to become more active in their lives (Class I). It is important to ask patients to be creative with physical activity implementation throughout the day; they need to recognize the benefit of doing brisk activity in multiple short bouts of 10 minutes at a time.

European guideline recommendations share many similarities to that of US groups, though they do also have subtle differences.⁵ The 2016 European Society of Cardiology (ESC) guidelines on cardiovascular disease prevention in clinical practice recommend a minimum of 150 minutes of moderate or at least 75 minutes of strenuous physical activity per week, aligned with their US counterparts (Class Ia). This goes a long way toward creating harmony across international guidelines, and strongly promotes a shared ideology on the importance of regular physical activity across the globe.

In an important break from the US guidelines, however, the European guidelines also include a recommendation to gradually increase exercise to 300 minutes per week of moderate physical activity or 150 minutes per week of strenuous physical activity as tolerated as a means of further improving cardiovascular wellness (Class Ia). They further carry specific recommendations for older populations or those with physically limiting conditions, such as relative intensity of exercise as a primary feature, as opposed to an absolute measure of what constitutes moderate or strenuous exercise.⁵ The ESC guidelines also include recommended bouts of exercise, with a preferred recommendation of 4-5 times per week, and preferably daily, of at least 10 minutes in length (Class IIa). Again, this is not included in the US recommendations. 

The European guidelines also discuss varying forms of physical activity, such as resistance and weight training, for which the guidelines leave fairly specific recommendations of 8-12 repetitions at 60-80% of the intensity of a single maximal repetition at least twice per week (for older individuals they recommend up to 70% of maximal intensity).⁵ Neuromotor physical activity focusing on balance and gait training is also emphasized, specifically in older adults, though the recommended amount per week is noted to be unknown. While the 2018 physical activity guidelines do discuss differing physical activity modalities, they are not a focus of the 2019 ACC/AHA recommendations.

Nutrition

Alongside physical activity, diet and nutrition are additional key components of cardiovascular health. The 2019 ACC/AHA guidelines promote nutrition as a main fixture of cardiovascular wellness, with a recommendation for a varied diet of fruit, vegetables, fish, legumes, and whole grains (Class I), as well as recommendations to reduce sodium, cholesterol, processed meats, and refined sugars (Class IIa recommendation).¹⁰ Sodium intake, a topic of some controversy as of late, is recommended to be kept at 1,500 mg/day or less, far below the average daily intake in the US of 3,409 mg/day, and notably below that of previous US recommendations for <2,300mg/day.^10,11 For those unable to reach 1,500 mg/day, they recommend at least a reduction of 1000 mg/day.

The guidelines also specifically focus on reducing saturated fats, recommending replacement with mono- and poly-unsaturated fats whenever possible (Class IIa). The 2019 ACC/AHA guidelines recommend diets with a higher vegetable to meat ratio, with plant-based, Mediterranean or "Pro-vegetarian" diets for most in the general population, and the Dietary Approaches to Stop Hypertension (DASH) diet for those with hypertension (Table 1). These recommendations are shared by the 2018 AHA/ACC cholesterol guidelines.

Table 1: Mediterranean and DASH Diet Recommendations

While not relaying specific amounts of various food groups, the guidelines cite several studies in support of these recommendations. One such study is the PREDIMED trial, which exhibited a significant reduction in cardiovascular events with a Mediterranean diet using olive oil (HR 0.69 (CI: 0.53-0.91), 96/2453 events) as compared to even a low-fat control diet (109/2450 events). These results were even more robust when adjusted for dietary adherence, with an adherence adjusted HR 0.42 (CI: 0.24-0.63) for a Mediterranean diet of olive oil or nuts versus low-fat control (the trial was notably retracted and republished after corrections to participant randomization).¹² A recommendation for the Mediterranean and DASH diets is shared by the lipid-focused 2018 AHA/ACC guideline on the management of blood cholesterol as an important method toward improving lipid profile and cardiovascular risk.¹ Additionally, the complete removal of trans-fats is advocated across US guidelines.

The 2016 ESC nutritional recommendations are largely similar to those of the US, also focusing on a plant-based or Mediterranean diet.⁵ The European guidelines, however, clearly delineate recommendations for daily intake within the various groups, specially noting >200g fruit daily, 30g unsalted nuts, 30 to 45g fiber, <5g salt, and saturated fat to be <10% of total daily energy intake. The authors highlight that for every 1% of saturated fat that is replaced polyunsaturated fats, the risk of ASCVD is reduced by 2-3%.

The 2019 ESC/European Atherosclerosis Society (EAS) guidelines for the management of dyslipidemia build on this with similar dietary pattern recommendations in addition to limiting cholesterol intake to <300mg/day.¹³ On the topic of sodium, their recommendation is slightly more lenient than that of their US counterpart, with a recommendation of <1,940mg sodium per day. With respect to sugar, the guidelines reference the World Health Organization (WHO) recommendation for <10% of daily energy intake to come from mono- or disaccharide sugars. This includes added refined sugar as well as sugar found in fruits/juices; whole fruits are much healthier than fruit juice.

The ESC guidelines also specifically mention a number of additional benefits of a plant-based diet, such as phytosterol intake – found in plant cell membranes and naturally part of a plant-based diet – as being possibly cholesterol-lowering and beneficial to cardiovascular health (this is not mentioned in US guidelines).⁵ Despite the above, the authors note that alongside a healthy and varied diet, no further vitamin or mineral supplementation should be necessary to maintain optimal nutritional values. Overall, the European guidelines note that a healthy diet is the "cornerstone of CVD prevention" in all individuals (Class Ib) and stress its importance in maintaining cardiovascular health.

Conclusions

Physical activity and nutrition remain the cornerstone of lifestyle management in cardiovascular disease prevention. As such, they are widely promoted by cardiovascular guideline committees around the world. While the guidelines are broad in their recommendations, key takeaways are present for clinicians as a guide. Physical activity guidelines present a very consistent recommendation for at least 150 minutes of moderate or 75 minutes of strenuous activity, or some combination each week.  While the most appropriate distribution of such activity is still of some debate, and mildly contentious among the various guidelines, the importance of physical activity above baseline every week is not left questioned. 

From a nutritional standpoint, the guidelines are also very consistent in recommending plant-based diets that limit red meat consumption – especially processed meat and saturated fat consumption – and emphasize a diet based on fruits, vegetables, nuts, and whole grains. Finally, all guidelines highlight the importance of shared decision-making and provider encouragement and teaching on the appropriate physical activity and dietary patterns. While the data will undoubtedly change as research on optimal physical activity and nutritional recommendations evolve, the primary conclusions of guidelines across the globe are consistent in their message. Greater emphasis and encouragement by clinicians, and indeed the healthcare system as a whole, will benefit patients for years to come.

References

1. Grundy SM, Stone NJ, Bailey AL, et al. 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA guideline on the management of blood cholesterol: a report of the American College of Cardiology/American Heart Association task force on clinical practice guidelines. J Am Coll Cardiol 2018:73:3168-3209.
2. Cosentino F, Grant PJ, Aboyans V, et al. 2019 ESC guidelines on diabetes, pre-diabetes, and cardiovascular diseases developed in collaboration with the EASD. Eur Heart J 2020;41:255-323.
3. Ferraro RA, Fischer NM, Xun H, Michos ED. Nutrition and physical activity recommendations from the United States and European cardiovascular guidelines: a comparative review. Curr Opin Cardiol 2020;35:508-16.
4. Eijsvogels TMH, Molossi S, Lee DC, Emery MS, Thompson PD. Exercise at the extremes: the amount of exercise to reduce cardiovascular events. J Am Coll  Cardiol 2016;67:316.
5. Piepoli MF, Hoes AW, Agewall S, et al. 2016 European Guidelines on cardiovascular disease prevention in clinical practice: the sixth joint task force of the European Society of Cardiology and other societies on cardiovascular disease prevention in clinical practice (constituted by representatives of 10 societies and by invited experts) developed with the special contribution of the European Association for Cardiovascular Prevention & Rehabilitation (EACPR). Eur Heart J 2016;37:2315-81.
6. Mandsager K, Harb S, Cremer P, Phelan D, Nissen SE, Jaber W. Association of cardiorespiratory fitness with long-term mortality among adults undergoing exercise treadmill testing. JAMA Netw Open 2018;1:e183605.
7. Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: executive summary: a report of the American College of Cardiology/American Heart Association task force on clinical practice guidelines. Circulation 2018;138:e426-e483.
8. Ekelund U, Steene-Johannessen J, Brown WJ, et al. Does physical activity attenuate, or even eliminate, the detrimental association of sitting time with mortality? A harmonised meta-analysis of data from more than 1 million men and women. Lancet 2016;388:1302-10.
9. Physical Activity Guidelines for Americans, 2nd edition. 2018. Available at: https://health.gov/sites/default/files/2019-09/Physical_Activity_Guidelines_2nd_edition.pdf. Accessed 08/01/2020.
10. Arnett DK, Blumenthal RS, Albert MA, et al. 2019 ACC/AHA guideline on the primary prevention of cardiovascular disease: a report of the American College of Cardiology/American Heart Association task force on clinical practice guidelines. Circulation 2019;140:e596-e646.
11. Quader ZS, Zhao L, Gillespie C, et al. Sodium intake among persons aged ≥2 years—United States, 2013–2014. MMWR Morb Mortal Wkly Rep 2017;66:324-38.
12. Estruch R, Ros E, Salas-Salvadó J, et al. Primary prevention of cardiovascular disease with a Mediterranean diet supplemented with extra- irgin olive oil or nuts. N Engl J Med 2018;378:e34.
13. Mach F, Baigent C, Catapano AL, et al. 2019 ESC/EAS Guidelines for the management of dyslipidaemias: lipid modification to reduce cardiovascular risk: the task force for the management of dyslipidaemias of the European Society of Cardiology (ESC) and European Atherosclerosis Society (EAS). Eur Heart J 2019;41:111-88.

Clinical Topics: Cardiovascular Care Team, Diabetes and Cardiometabolic Disease, Dyslipidemia, Prevention, Sports and Exercise Cardiology, Lipid Metabolism, Diet, Exercise

Keywords: Dyslipidemias, Walking, Jogging, Sedentary Behavior, Metabolic Equivalent, Blood Pressure, American Heart Association, Swimming, Weight Loss, Diabetes Mellitus, Type 2, Cardiovascular Diseases, Wakefulness, Physical Fitness, Vegetables, Fats, Unsaturated, Fabaceae, Sodium, Phytosterols, Vitamins, Nuts, Diet, Mediterranean, Fruit, Life Style

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