More than yearly deaths in the United States are attributed to cardiovascular CV disease resulting from a lack of physical activity. The association between physical inactivity and CV disease gained a foothold in the medical community in , when the American Heart Association AHA published information advocating the benefit of physical exercise in regards to improvements in hemodynamic, hormonal, metabolic, neurological and respiratory function[ 2 ].
As the association between physical inactivity and the increased risk of CV morbidity solidified, further data and studies supported the advantages of exercise on physical well-being. In the age group of years, individuals should accrue at least 60 min of moderate activity daily. Those in the group of years should perform at least min of moderate activity or at least 75 min of vigorous activity throughout the week.
Finally, individuals above the age of 65 years are recommended similar length and intensity exercise programs as the prior group, but with a focus on activities to help enhance balance and to prevent falls[ 3 ].
The inherent advantages of physical exercise stem from an increase in the cardiac output and an enhancement of the innate ability of muscles to extract and to utilize oxygen from the blood. This benefit is further compounded by the benefit physical exercise has on high-density lipoprotein cholesterol HDL-C [ 4 ], adipose tissue distribution[ 5 ], increased insulin sensitivity[ 6 ], improved cognitive function[ 7 ], enhanced response to psychosocial stressors[ 8 ], as well as determent of depression[ 9 ].
With the benefit of physical exercise well established, the question remains which type of exercise provides the most effective and efficient means to help deter CV disease. A recent meta-analysis published showed a decrease in the risk of all CV outcomes and diabetes mellitus incidence with increasing levels of physical activities[ 10 ].
Furthermore, cardiac rehabilitation, which is physical exercise based, is a promising field which showed a favorable outcome among patients with heart failure and post-CVD events[ 12 , 13 ].
The American College of Sports Medicine ACSM defines aerobic exercise as any activity that uses large muscle groups, can be maintained continuously and is rhythmic in nature[ 10 ]. As the name implies, muscle groups activated by this type of exercise rely on aerobic metabolism to extract energy in the form of adenosine triphosphate ATP from amino acids, carbohydrates and fatty acids. These activities can best be accessed via the aerobic capacity, which is defined by the ACSM as the product of the capacity of the cardiorespiratory system to supply oxygen and the capacity of the skeletal muscles to utilize oxygen[ 14 ].
The criterion measure for aerobic capacity is the peak oxygen consumption VO 2 , which can be measured either through graded exercise ergometry or treadmill protocols with an oxygen consumption analyzer or via mathematical formulas.
The value of peak VO 2 can be appreciated by a study performed by Vaitkevicius et al[ 15 ], in which the VO 2max was calculated along with other dimensions, to conclude that higher physical conditioning status was directly correlated with reduced arterial stiffness. Various studies have been published that prove the advantages of aerobic exercise in reversing and preventing CV disease.
Their study was performed on adult female Sprague-Dawley rats, which were placed into groups categorized based on induced myocardial infarctions MI with and without exercise and controls with and without exercise.
They were able to conclude the beneficial effects of aerobic training on cardiac remodeling and myocardial contractility[ 16 ]. Additionally, cardiac remodeling was evident in humans, much like the rat subjects in the previous study, as LV diameters declined and LV volumes increased in both the diastolic and systolic phases. Furthermore, aerobic exercise has been shown to have a positive impact on other dimensions of CV health. Several studies have shown that aerobic exercise improves the lipid profile, particularly increasing the HDL-C[ 18 ].
In an Australian study, aerobic exercise led to a small but statistically significant reduction in total cholesterol TC , low-density lipoprotein cholesterol LDL-C and triglycerides TG ranging in a span of 0. They also showed an increase in HDL-C with their aerobic exercise program of about 0. Similar results have been documented in children and adolescents, as well[ 20 ]. A positive correlation between biochemical signal markers, such as endothelin-I ET-1 and aerobic exercise was recently speculated by several studies.
Vascular endothelial cells produce ET-1, which functions as a vasoconstrictor[ 22 ] and promoter of atherosclerosis[ 23 ]. Maeda et al[ 24 ] were able to demonstrate a statistically significant positive linear correlation of increasing age with rising levels of ET They were also able to exhibit a visible reduction in ET-1 levels after a 3 mo aerobic exercise regimen[ 24 ].
While aerobic exercise appears to have some beneficial effects, its contribution is limited on frequency and quantity. Their research quantified 1 to 2.
Interestingly, they quantified any amount above that standard as being indifferent to the mortality risk, as that of sedentary individuals[ 25 ]. Anaerobic exercise has been defined by the ACSM as intense physical activity of very short duration, fueled by the energy sources within the contracting muscles and independent of the use of inhaled oxygen as an energy source[ 14 ].
Without the use of oxygen, our cells revert to the formation of ATP via glycolysis and fermentation. This process produces significantly less ATP than its aerobic counterpart and leads to the build-up of lactic acid. Exercises typically thought of as anaerobic consist of fast twitch muscles and include sprinting, high-intensity interval training HIIT , power-lifting, etc. Sustained anaerobic metabolism, in other words, anaerobic exercise, causes a sustained increase in lactate and metabolic acidosis and this transition point is referred to anaerobic threshold AT [ 26 ].
AT can be directly measured via frequent blood samples measuring the blood lactate level during a graded-exercise regimen. Once the blood lactate values are plotted, the point at which the curve makes a sudden sharp incline represents the AT. Other methods include portal lactate analyzers and mathematical formulas involving heart rate HR. Similar to aerobic exercise, anaerobic exercise may exert a potentially beneficial influence on the CV system.
CNP is synthesized by the endothelium and offers a protective effect through its effects on the vascular tone of blood vessels, as well as exerting antifibrotic and antiproliferative properties.
It produces a hyperpolarization effect on the smooth muscle layer of blood vessels, which causes vasodilatation[ 28 ]. CNP has also been reported to exert its nonproliferative effects on cardiac fibroblasts to help prevent cardiac aging through LV fibrosis via the cyclic guanosine monophosphate cGMP pathway[ 29 ].
In this study, twelve healthy young male subjects were divided into two groups based on their previous history of exercise. Once categorized into groups, the subjects were asked to participate in a thirty second high intensity exercise program, which encompassed the anaerobic exercise factor.
Blood samples were obtained from the subjects before exercise and then one minute, five minutes and thirty minutes after exercise and were tested for the levels of aminoterminal proCNP NT-proCNP , a biologically inactive peptide of CNP. The results showed a statistically significant increase of NT-proCNP level in the five minute mark post-exercise in the physically active group after anaerobic exercise.
Similar to aerobic exercise and their favorable effect on lipid metabolism, anaerobic exercises have been shown to have a positive influence on the lipid profile. A small European study composed of 16 obese subjects was able to show the increased benefits of an aerobic workout followed by anaerobic training, as compared to aerobic training alone.
I conducted a maximum HR determination session by doing 5 X 3 minute maximum effort hill intervals. My maximum HR was in accordance with the Karvonen formula and I found that the Karvonen zone calculations were very close to my perceived effort levels and I have made only minor modifications. So, I will suggest that the Karvonen formula may be a good place to start but do not feel constrained to modification of the zones as you see fit as this will affect the training effect calculation.
I have used the highest level as I train everyday and throughout the year. It is important to realize that the training effect will only be informative if you thoroughly and accurately establish your max HR and zone levels. It is well worth the effort and time to do this well. Although no reference is made by Firstbeat about the details of their algorithm, it seems apparent that they are at least utilizing an integrated total heartbeat measure, time spent in each zone, and the differential of your training session heartbeat function i.
Once established, the training effect calculation is stable and, at least in my experience, accurate. There are numerous ways to use the training effect data for analysis. Training effect data can be used on a daily basis to ensure that your scheduled workout was at the right intensity level and to provide feedback for any daily training program adjustments needed. Training effect data can also be used to monitor the longer term intensity periodization of your training program, particularly leading up to races.
The longer term perspective will give insight as to how your training has progressed and what specific periodization protocols work for you. All of this is important information to have to assist in reaching your ultimate potential. Often athletes rely heavily on detailed volume accumulation, be it time such as for Nordic skiers or distance such as for ultramarathon runners , with a less detailed understanding of the specific intensity attained for the workouts.
You will likely be exposed to athletes referring to consistent mile or 15 hour weeks as a summary of their training regimen. Without the corresponding intensity data, the mileage or time can be quite meaningless as it relates to training progression. The training effect data can very effectively supplement other training data to give a more complete picture of the efficacy of your program. Runners will often report weekly mileage or, more appropriately, a rolling 7 day or other relevant period average value for mileage although many adhere to a calendar week due primarily to constraints associated with their work schedule.
Similarly, a rolling average value for training effect can also be used as a metric and one that is perhaps better suited to providing solid guidance for intensity management and the inevitable needed modifications. It can also provide warning as to potential over-training since consistent elevated training effect for known lower intensity workouts is a direct indication of over-training.
Firstbeat defines various ranges of training effect according to the impact on training: According to coaches that I have consulted with, these data indicate that I have spent way too much time in L3 and have not achieved an optimal fitness level for the time spent training about hrs. It is suggested that although I have importantly built a considerable base, a more structured program with more extended periods of intensity followed by more extended periods of recovery will lead to higher performance and optimal tapping of my ultimate ability.
I am now designing a more structured program to accomplish this with a couple of focus races as goals along the way. This makes the training effect data quite valuable to those interested in achieving their potential. This is not to say that utilization of perceived effort is flawed, just that the TE gives a more analytic, repeatable, and likely reliable, assessment of the intensity for a given workout.
It is a tool not a requirement. Further analysis of these data however, reveals a more robust metric: intensity minutes. A certain level of calibration is necessary to interpret these data and this can be developed over time for each individual. Another way to analyze the data is as a 7 day rolling total intensity minutes as plotted below.
Once again a calibration of these data to personal capability and effectiveness can be developed with time. An interesting correlation that I have found is that my intensity minute values are highly correlated with accumulated vertical ascension.
Plotted below is the corresponding 7 day rolling total vertical ascension. This correlation may be due to a particularly inefficient climbing ability and may be identifying an area where I should be focusing in fitness and technique.
Certainly there are numerous other extractable observations from all of this data, some that may provide insight and others that may just confuse. My use of this data has been to develop a detailed structured training plan going forward now that I have re-established a proper training base in the past I will give progress updates on the usefulness of the training effect and intensity minute metrics in the structured program in subsequent posts.
I hope that I have demonstrated the utilization of Training Effect and the derivative metric of intensity minutes as a useful tool for developing, analyzing, and monitoring structured training programs. These data combined with dedicated execution upon a rational training program can help anyone achieve their endurance athletic goals.
This post summarizes a work in process and I am by no means expert in this area. I have posted and update on this subject as of 21 October Interested in learning how to improve your anaerobic performance capacity?
Check out our Anaerobic Training Effect. The only way to improve these diverse aspects of performance is to vary the focus of your activities. This variation is essential to becoming a well-rounded performer, and to find the right workout at the right time.
It is important to understand the impact and role of each workout in your repertoire. When deciding how hard you should train, it is the goal that matters. Are you on a mission to boost your VO2max to the Superior level, or simply eager to feel healthy and energetic? The more ambitious your goals, the greater the intensity and the overall amount of exercise must be. This is also the reason why the improvement of fitness is fastest for the beginners.
The fitter you get, the more effort it takes to get results. Luckily, the feedback you get from Aerobic Training Effect keeps up with your development to ensure personalized analysis based on your current fitness level and training history. If you then train wisely, you may finish the same 5k run in 30 minutes — with TE of 2.
Your aerobic fitness has improved, and you need to run even faster to further improve your VO2max. Last but not least, few words about the physiology of Aerobic Training Effect. The basis lies behind EPOC, a physiological measure that reflects the recovery demand of your body.
It stands for Excess Post-Exercise Oxygen Consumption and tells how much oxygen — used at a cellular level to convert nutrients into energy — your body needs to restore itself and adapt in response to your efforts. EPOC is a measure of the work your body does to prepare for the next challenge. The harder the exercise, the more energy your body expends to recover, the higher your EPOC — and the higher your Aerobic Training Effect.
Traditionally EPOC has been measured in laboratories, but for well over a decade, Firstbeat has been pioneering the ability to predict EPOC values using heartbeat data.
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