Respiratory Training: A Neglected but Significant Training Modality

Jesse Oswald • May 8, 2024

Respiratory Training

Respiratory training is the deliberate modification of how we usually breathe throughout the day by implementing specific exercises and techniques to eventually improve oxygen uptake, lung function, and overall well-being and enhance athletic performance. Respiratory training aims to strengthen the diaphragm, which is the primary muscle of respiration, as well as the inspiratory rib cage muscles. This will eventually increase lung capacity and optimize oxygen delivery to the body’s tissues, including muscles, at rest and during exercise.

 

Respiratory training can be applied through various techniques based on the ultimate goal and what best suits the individual. The most popular type of respiratory training is diaphragmatic breathing. It can be performed in a supine position, sitting or standing, based on the practice level of the individual. When you first learn the diaphragmatic breathing technique, you should practice it lying on your back. Bend your knees and support your head using a pillow or a folded towel to relax your neck and shoulder muscles. Place one hand on your upper chest and the other on your belly below your ribcage to feel your diaphragm moving up and down. Breathe slowly through your nose so your stomach pushes out, causing your hand to rise. The hand that lies on your chest should remain as still as possible. To exhale, pursue your lips as if you are going to whistle or gently blow on a hot drink. Exhale slowly and gently through your pursed lips by tightening your abdominals so that your stomach moves in.

 

Two other common forms of respiratory training include inspiratory muscle training (IMT) and yogic breathing. IMT involves breathing exercises using a pressure threshold device to strengthen the inspiratory muscles, such as the external intercostals. It’s a form of resistance training for these muscles since it strengthens them, improving stamina and reducing breathing fatigue. It is performed sitting or standing, where the individual puts on a nose clip, holds the IMT device by the handle grip, and places the mouthpiece in the mouth. They breathe out as far as they can and take a fast, forceful breath through their mouth, trying to breathe as much air as they can while expanding their chest. They then breathe out slowly with minimal effort while letting their shoulders relax. Yogic breathing, also referred to as pranayama, is mainly practiced through the guidance of a certified yoga instructor. It involves breath control via patterns and variations in respiration rate, with specific instructions regarding the number of breaths over a certain period of time. Some variations of yogic breathing include alternate nostril, paced, and box breathing.

 

Respiratory training is mainly used by people suffering from breathing problems such as asthma and chronic obstructive pulmonary disease (COPD). COPD is a group of respiratory diseases that cause airflow obstruction and breathing-related problems, such as dyspnea. It includes emphysema and chronic bronchitis and is the fourth leading cause of death in the US. However, respiratory training is also regularly used by athletes who wish to improve their sports performance by strengthening their breathing muscles, thus improving breathing stamina and strength, and eventually endurance during aerobic exercise.

 

The benefits of respiratory training are due to a combination of physiological mechanisms. Two of the main mechanisms are increased oxygen delivery and improved tissue oxygenation. Respiratory training allows increased amounts of oxygen to enter the bloodstream through the lungs, enhancing oxygen delivery to the body’s tissues and organs, such as the working muscles. The improved tissue oxygenation is crucial for the proper functioning of cells. It promotes metabolic processes which require oxygen to be attained and produce energy, which is valuable for accomplishing vital cellular functions. The increased cellular energy produced is in the form of adenosine triphosphate (ATP). ATP is the primary energy source for cells and derives from this increased metabolic function attained through respiratory training. Another vital mechanism through which respiratory training works is wound healing. Adequate oxygen levels are necessary for tissue repair and regeneration as well as angiogenesis (the growth of new blood vessels) in the injured area.

 

Regarding mechanisms around lung mechanics per se, respiratory training alleviates the strain on the respiratory system by strengthening inspiratory muscles, better controlling breath, and eventually making breathing easier. Therefore, it reduces the effort required to breathe (work of breathing) and improves oxygen exchange in the lungs. This is particularly helpful when oxygen demand increases, as happens in pulmonary diseases and/or during exercise. Especially when the intensity of exercise increases, the breathing volume or ventilation must also rise to cope with the oxygen demand. The inspiratory muscles must contract more forcefully and rapidly to keep pace with the substantial increase in metabolism, and this process can be attained through respiratory training.

 

Each proposed mechanism above can lead to several benefits that respiratory training may offer an individual who regularly practices it. One of the most important benefits associated with the first two mechanisms described above is the reduction of lung disease symptoms, such as shortness of breath (at rest and during exercise), whizzing, chest tightness, and lack of energy. Therefore, people suffering from pulmonary diseases can have a much better quality of life by participating and enjoying all aspects of life. By improving lung health-related symptoms, respiratory training can vastly enhance sleep quality. Many people with compromised lung function face sleeping-related breathing disorders, with sleep apnea being the most common. Engaging in respiratory training techniques can significantly decrease these symptoms, resulting in better sleep and reduced daytime fatigue.

 

Nevertheless, as already mentioned, respiratory training can also lead to improved physical performance, which most athletes long for. Elevated oxygen uptake can increase the amount of lung capacity a person is able to use per breath (tidal volume) as well as the oxygen delivered to the working muscles during exercise, thus improving cardiovascular endurance during exercise or sports activities, such as running and cycling. Lung capacity and cardiovascular endurance are also assessed through the active test performed by the PNOĒ metabolic analyzer. Their respective metrics in the PNOĒ active reports are expressed as aerobic health and respiratory capability, respectively. Respiratory training can further enhance athletic performance by contributing to the recovery process after exercise. It helps reduce muscle soreness, accelerate tissue repair, and promote faster recovery between workouts. This increased recovery capacity is also assessed and depicted in the PNOĒ active reports.

Respiratory training also strengthens the inspiratory muscles and improves breath control at rest and during exercise. Therefore, it helps improve breathing and posture as well as breathing and stability, metrics provided in the PNOĒ resting and active metabolic reports, respectively. As a result, musculoskeletal problems, especially in the spine, arising from not breathing properly, thus not properly activating the deep core muscles, especially during exercise, can be avoided. Lastly, respiratory training can improve brain oxygenation, enhancing cognitive performance, improved concentration, and mental clarity at rest and during exercise. These are also metrics assessed through the PNOĒ metabolic analyzer (the breathing & cognition metrics in both the resting and active metabolic reports).

 

Respiratory training is the deliberate modification of how we usually breathe by implementing specific exercises and techniques. Its benefits are due to a combination of mechanisms, including increased oxygen delivery, improved tissue oxygenation, increased energy (ATP) levels, and enhanced respiratory muscle strength. These mechanisms work together to reduce lung disease symptoms and improve sleep quality, sports performance, recovery, and brain function.

References

  • Ambrosino N. Inspiratory muscle training in stable COPD patients: enough is enough? Eur Respir J. 2018;51(1):1702285
  • Basso-Vanelli RP, Di Lorenzo VAP, Labadessa IG, Regueiro EMG, Jamami M, Gomes ELFD, Costa D. Effects of inspiratory muscle training and calisthenics-and-breathing exercises in COPD with and without respiratory muscle weakness. Respir Care. 2016;61(1):50-60
  • Bostanci O, Mayda H, Yilmaz C, Kabadayi M, Yilmaz AK, Ӧzdal M. Inspiratory muscle training improves pulmonary functions and respiratory muscle strength in healthy male smokers. Respir Physiol Neurobiol. 2019;264:28-32
  • de Medeiros AIC, Fuzari HKB, Rattesa C, Brandão DC, de Melo Marinho PÉ. Inspiratory muscle training improves respiratory muscle strength, functional capacity and quality of life in patients with chronic kidney disease: a systematic review. J Physiother. 2017;63(2):76-83
  • HajGhanbari B, Yamabayashi G, Buna TR, Coelho JD, Freedman KD, Morton TA, Palmer SA, Toy MA, Walsh C, Sheel AW, Reid DW. Effects of respiratory muscle training on performance in athletes: a systematic review with meta-analyses. J Strength Cond Res. 2013;27(6):1643-1663
  • Illi SK, Held U, Frank I, Spengler CM. Effect of respiratory muscle training on exercise performance in healthy individuals: a systematic review and meta-analysis. Sports Med. 2012;42(8):707-724
  • Walterspracher S, Pietsch F, Walker DJ, Röcker K, Kabitz H-J. Activation of respiratory muscles during respiratory muscle training. Respir Physiol Neurobiol. 2018;247:126-132

An Ounce of Prevention - Hyperion Health Blog

A woman is helping an older woman do exercises on an exercise ball in a gym.

What is a Kinesiologist?

By Jesse Oswald • January 29, 2025
What is a Kinesiologist?
A woman is wearing an oxygen mask while running on a treadmill.

Predicting Medical Costs with VO2max

By Jesse Oswald • January 20, 2025
Highlights Healthcare expenses are skyrocketing, with consumers and employers facing the significant brunt. Identifying those likely to get sick is critical as our resource-strapped healthcare system should focus on those likely to become the most significant burden to the system. VO2 max is a crucial longevity indicator that can also accurately predict healthcare expenses. The rampant chronic disease epidemic and the resulting surge in medical expenses is one of the most dire problems of modern societies, probably only second to climate change. Healthcare inflation is on a meteoric rise, and for those with limited or no healthcare coverage, a medical emergency is the equivalent of personal bankruptcy. A dire problem for employers In the US, employers and consumers who face rising health insurance premiums and astronomical out-of-pocket medical expenses feel the brunt of rising healthcare costs. Such is the problem that even large, well-capitalized corporations choose to send employees overseas for specific medical procedures since the cost of traveling and treatment in a foreign country is lower than the cost of care in the US. Another startling example is the infamous "northern caravan," a term that describes people with diabetes in the northern states who travel to Canada to secure their insulin supply. According to McKinsey , a survey conducted among over 300 employers highlighted that the average increase in the cost of health benefits over the past three years has been within the range of 6 to 7 percent. This survey also indicated that any rate increases exceeding 4 to 5 percent were deemed unsustainable. Interestingly, 95 percent of the surveyed employers expressed willingness to contemplate reducing benefits if costs surged by 4 percent or more. The primary cost-control measures that these employers indicated they might explore included elevating the portion of premium costs covered by employees and a potential transition to high-deductible health plans. Why is Breath Analysis relevant? Vis-a-vis this problem, the early and accurate estimation of who will get sick and how much they will cost is as critical as the treatment itself. The reason is that no other method of accurately identifying at-risk populations exists; it helps focus our scarce prevention resources and attention on those most in need. Breath analysis, AKA VO2max or metabolic testing, is an assessment that reveals two key biomarkers that provide significant predictive value for one's likelihood of developing costly chronic conditions. These two biomarkers are VO2max and the Respiratory Exchange Ratio. In this article, we will dive into VO2max to understand why it's a critical reflection of our overall health and, consequently, a window into our future healthcare spend. What is VO2max? Let's start with the basics. What is VO2max? VO2 max is the maximum amount of oxygen the human body can absorb. It is measured in terms of milliliters of oxygen consumed per kilogram of body weight. The below formula below indicates how VO2max is calculated: The numerator indicates the volume of oxygen your heart, lungs, and cells can absorb, expressed in milliliters per minute. The denominator indicates the weight of the individual represented in kilograms. 
There are many different types of fats in this picture.

Dietary Fat: An Essential Dietary Component Rather than the root of all Nutritional Health Issues

By Jesse Oswald • January 13, 2025
Key points A total fat intake between 20-35% ensures sufficient intake of essential fatty acids and fat-soluble vitamins Omega-6 PUFAs are primarily found in vegetable oils, while omega-3 PUFAs are primarily found in fatty fish and fish oils Both omega-3 PUFAs and MUFAs have established benefits for cardiovascular disease TFAs are the only dietary lipids that have a strong positive relationship with cardiovascular disease Omega-3 PUFA supplementation increases the beneficial bacteria of the human microbiome Over the last three decades, there has been a great revolution against fat due to its suspected association with several nutritional health issues, especially cardiovascular disease. There was a tremendous amount of evidence that indicated dietary cholesterol and saturated fat as the main culprits of cardiovascular disease, thus morbidity and mortality. It was when all the low-fat and no-fat dairy products started to launch, promising even complete substitution of the cholesterol-lowering heart medication if these products were exclusively consumed. Let’s start from the beginning. Dietary fat intake can vary significantly and still meet energy and nutrient needs. International guidelines suggest a total fat intake between 20% and 35% of the daily caloric consumption. This range ensures sufficient intake of essential fatty acids and fat-soluble vitamins. Not only does the quantity of the ingested fat matter, but most importantly, its quality. Some dietary fats have beneficial effects, with a significant role in maintaining good health, while others may threaten it. Which are, after all, the dietary fats? Dietary fats is a rather heterogeneous group of organic compounds, including four main types of fat, which are elaborately described in the following sections of this article. Polyunsaturated fatty acids (PUFAs) Polyunsaturated fatty acids (PUFAs) have two or more carbon-carbon double bonds. Omega-6 PUFAs and omega-3 PUFAs are the main types of PUFAs and are classified according to the location of the first unsaturated bond (sixth and third carbon atom, respectively). Alpha-Linolenic acid (ALA), docosahexaenoic acid (DHA), docosapentaenoic acid (DPA), and eicosapentaenoic acid (EPA) are the most important omega-3 PUFAs. ALA is an essential fatty acid that can only be obtained from diet and can be converted into EPA and then to DHA, but the rate of this conversion is finite, approximately 7.0%–21% for EPA and 0.01%–1% for DHA. In the same way, the most important omega-6 PUFAs are linoleic acid (LA) and arachidonic acid (ARA). LA is an essential fatty acid that, in order to give rise to ARA, needs to be ingested through the diet as the human body cannot synthesize it. The recommended intake for total PUFA ranges between 5% and 10% of the total energy intake, while a total omega-3 PUFA intake of 0.5%–2% and a total omega-6 PUFA intake of 2.5%-5% is suggested. A dietary ratio of omega−6/omega−3 PUFA is recommended to be 1:1–2:1 to balance their competing roles and achieve health benefits. Omega-6 and omega-3 PUFAs Omega-6 PUFAs, in the form of LA, are plentiful in most crop seeds and vegetable oils, such as canola, soybean, corn, and sunflower oils. In contrast to omega-6 PUFAs, omega-3 PUFAs are obtained from a limited range of dietary sources. Flax, chia, and perilla seeds are rich in ALA, with significant amounts also detected in green leafy vegetables. The consumption of fatty fish, such as salmon, sardines, tuna, trout, and herring, provides high amounts of EPA and DHA. Besides fish and their oils, small amounts of omega-3 PUFAs are also detected in red meat like beef, lamb, and mutton. All the above dietary sources provide EPA, DPA, DHA, LA, and ARA in different amounts, and their intake is necessary for normal physiological function. PUFAs play a critical role in many chronic diseases, affecting human cells by regulating inflammation, immune response, and angiogenesis. Omega-3 PUFAs’ role against hypertriglyceridemia has been clarified, and research indicates that systematically consuming oily fish can contribute to general heart protection. Supplementation with omega-3 PUFAs could potentially lower the risk of several cardiovascular outcomes, but the evidence is stronger for individuals with established coronary heart disease. Moreover, adequate EPA and DHA levels are necessary for brain anatomy, metabolism, and function. Although the mechanisms underlying omega-3 PUFAs' cardioprotective effects are still poorly understood, several studies have been conducted in this direction. Unfortunately, that does not hold true for their omega-6 counterparts, for which controversial emerging data tend to show anti-inflammatory behavior that needs to be further studied. Monounsaturated fatty acids (MUFAs) In contrast to PUFAs, monounsaturated fatty acids (MUFAs) are easily produced by the liver in response to the ingestion of carbohydrates. The main MUFA is oleic acid, found in plant sources, such as olive oil, olives, avocado, nuts, and seeds, while minimal amounts are also present in meat, eggs, and dairy products. Specific guidelines around MUFAs’ dietary consumption do not exist. Therefore, MUFAs are recommended to cover the remaining fat intake requirements to reach the total daily fat intake goal. A growing body of research shows that dietary MUFAs reduce or prevent the risk of metabolic syndrome, cardiovascular disease (CVD), and hypertension by positively affecting insulin sensitivity, blood lipid levels, and blood pressure, respectively. Moreover, olive oil contains several bioactive substances, possessing anti-tumor, anti-inflammatory, and antioxidant qualities. According to a meta-analysis, consuming olive oil was linked to a lower risk of developing any sort of cancer, especially breast cancer and cancer of the digestive system. Another study found that an isocaloric replacement of 5% of the energy from saturated fatty acids (SFAs) with plant MUFAs led to an 11% drop in cancer mortality over a 16-year follow-up period. Therefore, including MUFAs in the everyday diet offers multifaceted benefits in chronic disease prevention and management, including cancer and general health promotion.  Saturated fatty acids (SFAs) Saturated fatty acids (SFAs) form a heterogeneous group of fatty acids that contain only carbon-to-carbon single bonds. Whole-fat dairy, (unprocessed) red meat, milk chocolate, coconut, and palm kernel oil are all SFA-rich foods. These fatty acids have distinct physical and chemical profiles and varying effects on serum lipids and lipoproteins. Stearic, palmitic, myristic, and lauric acids are the principal SFAs found in most natural human diets. Dietary practice and guidelines recommend limiting SFA intake to <10% of the total energy (E%), while the American Heart Association suggests an even lower intake of <7 E% because total saturated fat consumption and LDL-C levels are positively correlated. However, the role of SFAs in CVDs is quite complex, and the evidence is heterogeneous. In a recent study with a 10.6-year follow-up period, which included 195,658 participants, there was no proof that consuming SFAs was linked to developing CVD while replacing saturated fat with polyunsaturated fat was linked to an increased risk of CVD. Moreover, according to 6 systematic reviews and meta-analyses, cardiovascular outcomes and total mortality were not significantly impacted by substituting saturated fat with polyunsaturated fat. Even if these analyses were to be challenged, due to heterogenous evidence, the possible reduction in CVD risk associated with replacing SFAs with PUFAs in several studies may not necessarily be an outcome of SFAs’ negative effect but rather a potential positive benefit of PUFAs. Regarding SFAs' effect on different types of cancers, associations of their intake with an increased risk of prostate and breast cancer have been indicated. Conversely, a meta-analysis showed no link between SFA intake and a higher risk of colon cancer; similarly, consuming MUFAs, PUFAs, or total fat did not affect colon cancer risk. Hence, the role of SFA consumption in preventing, promoting, or having a neutral role in serious chronic diseases has not been fully elucidated yet. Trans fatty acids (TFAs) Trans fatty acids (TFAs) are created industrially by partially hydrogenating liquid plant oils or can be naturally derived from ruminant-based meat and dairy products. TFAs are highly found in commercial baked goods, biscuits, cakes, fried foods, etc. Guidelines regarding TFAs are stringent and limit TFA intake to <1% of energy or as low as possible. In 2015, the US Food and Drug Administration declared that industrial TFAs are no longer generally recognized as safe and should be eliminated from the food supply as their consumption is strongly linked to various CVD risk factors. Specifically, TFA intake raises triglycerides and increases inflammation, endothelial dysfunction, and hepatic fat synthesis, leading to a significantly increased risk of coronary heart disease (CHD). A meta-analysis suggested that increased TFA intake led to an increase in total and LDL-cholesterol and a decrease in HDL-cholesterol concentrations. Data also indicates that TFAs may influence carcinogenesis through inflammatory pathways, but the reported data are debatable. A recent study investigated the effects of all types of dietary fat intake on CVD risk. While PUFA, MUFA, and SFA intake were not linked to higher CVD risk, dietary TFA intake showed a strong association with CVD risk. Analysis indicated PUFA intake and CVD risk were inversely correlated, and the relative risk of CVD was reduced by 5% in studies with a 10-year follow-up. Dietary lipids and the human microbiome Dietary lipids also affect human microbiota composition. Studies have identified a close association between the human microbiome and metabolic diseases, including obesity and type 2 diabetes. Diets with a high omega-6 PUFA, SFA, and TFA intake increase the amount of many detrimental bacteria in the microbiome and reduce the amount of the beneficial ones, altering the microbiota composition and inducing inflammation via the secretion of pro-inflammatory cytokines. These bacteria may disrupt the gut barrier function, allowing lipopolysaccharides (LPS) translocation, which are bacterial toxins. This condition is linked to metabolic perturbations such as dyslipidemia, insulin resistance, non-alcoholic fatty liver disease (NAFLD), and CVD. On the contrary, omega-3 PUFA (EPA and DHA) supplementation increases beneficial bacteria and limits harmful ones, enhancing intestinal barrier functioning and preventing LPS translocation and its implications. Omega-3 PUFA supplementation has also been studied as a means of mental health disorders management, but the evidence is still controversial. A possible protective impact of fish consumption on depression has been suggested by various studies, as well as a possible protective effect of dietary PUFAs on moderate cognitive impairment. A recent review of meta-analyses indicated that omega-3 PUFA supplementation might have potential value in mental health disorders, but data credibility is still weak. Dietary lipids and obesity Last but not least, obesity and its management is another field that dietary lipids intake seems to impact with their mechanisms. A diet high in PUFA has been shown to lower the total mass of subcutaneous white adipose tissue (the predominant fat type in human bodies), reduce blood lipid levels, and improve insulin sensitivity. In a study comparing PUFA and MUFA isocaloric intake, PUFA was more advantageous and lowered visceral adiposity in patients with central obesity. By stimulating brown adipose tissue, which aids energy expenditure through its elevated thermogenic activity, omega-3 PUFAs seem to elicit these positive effects in fat tissue, thus being useful in preventing and/or managing obesity. Another related study compared PUFA to SFA overfeeding in dietary surplus conditions that aimed to increase weight by 3%. While SFA overfeeding led to weight gain, primarily through the expansion of the visceral adipose tissue, PUFA overfeeding also led to weight gain, but because of a greater expansion of lean tissue mass. To sum up, dietary fats are an essential part of the human diet with many important physiologic functions, including cell function, hormone production, energy, and nutrient absorption. Moreover, dietary fat consumption is associated with positive outcomes in regard to cardiovascular disease, metabolic syndrome, cancer, and depression. Therefore, there is no reason to demonize this valuable dietary component, incriminating it for irrelevant adverse health outcomes, primarily weight loss failure and obesity. References 1. Astrup A, Magkos F, Bier DM, Brenna JT, de Oliveira Otto MC, Hill JO, King JC, Mente A, Ordovas JM, Volek JS, Yusuf S, Krauss RM. Saturated fats and health: A reassessment and proposal for food-based recommendations: JACC State-of-the-Art review. J Am Coll Cardiol. 2020;76(7):844-857. DOI: 10.1016/j.jacc.2020.05.077 2. Bojková B, Winklewski PJ, Wszedybyl-Winlewska M. Dietary fat and cancer-Which is good, which is bad, and the body of evidence. Int J Mol Sci. 2020;21(11):4114. DOI: 10.3390/ijms21114114 3. Custers, Emma EM, Kiliaan, Amanda J. Dietary lipids from body to brain. Prog Lipid Res. 2022;85:101144. DOI: 10.1016/j.plipres.2021.101144 4. de Souza RJ, Mente A, Maroleanu A, Cozma AI, Ha V, Kishibe T, Uleryk E, Budylowski P, Schünemann H, Beyene J, Anand SS. Intake of saturated and trans unsaturated fatty acids and risk of all cause mortality, cardiovascular disease, and type 2 diabetes: systematic review and meta-analysis of observational studies. BMJ. 2015;351:h3978. DOI: 10.1136/bmj.h3978 5. Gao X, Su X, Han X, Wen X, Cheng C, Zhang S, Li W, Cai J, Zheng L, Ma J, Liao M, Ni W, Liu T, Liu D, Ma W, Han S, Zhu S, Ye Y, Zeng F-F. Unsaturated fatty acids in mental disorders: An umbrella review of meta-analyses. Adv Nutr. 2022;13(6):2217-2236. DOI: 10.1093/advances/nmac084 6. Liu AG, Ford NA, Hu FB, Zelman KM, Mozaffarian D, Kris-Etherton PM. A healthy approach to dietary fats: understanding the science and taking action to reduce consumer confusion. Nutr J. 2017;16(1):53. DOI: 10.1186/s12937-017-0271-4 7. Poli A, Agostoni C, Visioli F. Dietary fatty acids and inflammation: Focus on the n-6 series. Int J Mol Sci. 2023;24(5):4567. DOI: 10.3390/ijms24054567 8. Saini RK, Keum Y-S. Omega-3 and omega-6 polyunsaturated fatty acids: Dietary sources, metabolism, and significance-A review. Life Sci. 2018;203:255-267. DOI: 10.1016/j.lfs.2018.04.049 9. Saini RK, Prasad P, Sreedhar RV, Naidu KA, Shang X, Keum Y-S. Omega-3 polyunsaturated fatty acids (PUFAS): Emerging plant and microbial sources, oxidative stability, bioavailability, and health benefits-A review. Antioxidants (Basel). 2021;10(10):1627. DOI: 10.3390/antiox10101627 10. Zhao M, Chiriboga D, Olendzki B, Xie B, Li Y, McGonigal LJ, Maldonado-Contreras A, Ma Y. Substantial increase in compliance with saturated fatty acid intake recommendations after one year following the American Heart Association diet. Nutrients. 2018;10(10):1486. DOI: 10.3390/nu10101486 11. Zhu Y, Bo Y, Liu Y. Dietary total fat, fatty acids intake, and risk of cardiovascular disease: a dose-response meta-analysis of cohort studies. Lipids Health Dis. 2019;18:91. DOI: 10.1186/s12944-019-1035-2
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