People with certain health conditions or those using high doses may be more likely to experience this effect. Medical monitoring programs also collect information about side effects. However, some post-marketing reports—cases that are reported after the drug is approved—have included complaints of palpitations or heart racing. Doctors often recommend checking for these risk factors before starting TRT. The way the testosterone is given—such as through injections or gels—may also change the chances of this happening. However, the percentage is low and varies depending on the study. Some people on TRT report feelings of their heart "racing" or beating harder. It plays a key role in many body functions, including muscle growth, bone health, mood, and sex drive. This article explores what is known, what is still being studied, and what men using TRT should be aware of when it comes to their heart. Hormones work with many body systems, including the brain, muscles, blood vessels, and immune system. There are many reasons why someone might feel a faster heartbeat after starting TRT. Since the heart is such an important organ, even small changes in heart function can raise concern. Additional investigation using biologically active levels of testosterone is required to further elucidate the association between low testosterone levels and severity of CAD. Although Kabakci et al21 controlled for subclinical CAD by assessing cardiac catheterization results of both cases and controls, they performed their analysis using total and free testosterone levels. On the other hand, some investigators have found no association between endogenous testosterone levels and the incidence of CAD. BT indicates bioavailable testosterone; CAD, coronary artery disease; CCS, case–control study; CS, cohort study; ECG, electrocardiogram; FAI, free androgen index; FT, free testosterone; H&P, history and physical exam; PCS, prospective cohort study; TT, total testosterone. However, it is widely accepted that men experience a gradual decline in their testosterone levels with increasing age,7–12 and male sex has long been considered a strong risk factor for CAD. The past 2 decades have witnessed a significant increase in the number of prescriptions for testosterone replacement therapy. These authors have investigated a possible association between levels of testosterone and markers of inflammation. Third, increased abdominal obesity may cause reduced testosterone secretion by negatively affecting the hypothalamus‐pituitary‐testicular axis. On the other hand, given that adipose tissue has a higher concentration of the enzyme aromatase, it could be that increased adipose tissue results in more testosterone being converted to estrogen, thereby causing hypogonadism. Corona et al demonstrated in their meta‐analysis that testosterone replacement therapy resulted in a decrease of 2.19% in fat mass.26 This discovery was confirmed in animal models as well.74 The longitudinal Cardiovascular Health Study failed to find an association between total and free testosterone levels and either incident CVD or mortality in older men. Many population-based studies have found an inverse correlation between endogenous testosterone levels and all-cause and cardiovascular mortality, especially in older men. The Massachusetts Male Aging Study established that testosterone levels peak around the age of 30 years, followed by a decline of 1%-2% annually.8 This observation led to an interest in exploring the association between low testosterone concentrations and cardiovascular risk. It is essential to address these factors to maintain optimal testosterone levels and promote healthy heart rate variability. This imbalance in hormone levels can disrupt the autonomic nervous system’s functioning, leading to reduced HRV and potentially increased cardiovascular risk. In its assessment of CV risks and T therapy, the FDA identified a total of only 4 studies suggesting an increased risk, yet none provided solid evidence to support this. Two recent observational studies reported increased CV risks in men who received testosterone prescriptions.17,18 Although they gained a significant amount of media attention, neither study provided credible evidence of increased CV risk. For those with heart issues or sensitivity to changes in hormones, these ups and downs may be uncomfortable. These differences can also influence the heart, including how fast it beats and whether there are changes in blood pressure or rhythm. These effects are especially important in people with preexisting heart problems. For others, it may be safe if they are carefully monitored and their heart disease is well controlled. Adding testosterone could potentially make these symptoms worse if the heart is forced to work harder. Heart failure is a condition where the heart does not pump blood as well as it should. Finally, Haddad et al used only 6 articles to perform their meta‐analysis for adverse cardiovascular events, which included 161 men in the testosterone replacement group and 147 men in the placebo group. Calof et al did not find a significant difference in the rate of cardiovascular events between the testosterone replacement group and the placebo group.146 Specifically, the authors found no statistically significant differences between the 2 groups in the rates of atrial fibrillation, atrial arrhythmia, myocardial infarction, chest pain or ischemia, coronary procedures including coronary artery bypass grafting, vascular events, and cerebrovascular events. Therefore, it is reasonable to assume that reduced levels of testosterone in CHF patients would result in decreased exercise capacity. Although testosterone was shown to significantly improve exercise capacity, none of the studies found a significant change in the LVEF.140–143 New York Heart Association class was shown to improve in 2 of the studies included in the meta‐analysis.144 Thirty‐five percent of the patients in the testosterone group (20 of 57) experienced an improvement of ≥1 New York Heart Association class in their functional capacity compared with only 9.8% of patients in the placebo group (5 of 51). Interestingly, Jankowska et al also discovered that the only predictor of the extent of deterioration in exercise capacity, as measured by peak VO2 and peak O2 pulse, was the magnitude of reduction in circulating testosterone levels. Not only did Jankowska et al demonstrate that men with CHF have significantly reduced levels of total and free testosterone, the authors were also able to demonstrate that with worsening severity of CHF, there was a significant stepwise decrease in the levels of both total testosterone and estimated free testosterone. In a study of 208 men with CHF and a median left ventricular ejection fraction (LVEF) of 33%, Jankowska et al demonstrated a statistically significant prevalence of testosterone deficiency among men with CHF who were either ≤45 or ≥66 years old.137 Levels of estimated free testosterone were also shown to be significantly reduced among CHF patients. Testosterone replacement therapy (TRT) can be an effective treatment option for men with low testosterone levels and decreased HRV. However, various factors, such as aging, lifestyle, and underlying health conditions, can affect testosterone levels and HRV. They can assess your hormone levels, evaluate your heart rate variability, and recommend appropriate treatment options, including TRT, if necessary. This article will explore the connection between testosterone levels and HRV and its implications for men’s health. In a comprehensive overview of systematic reviews to date, Onasanya and colleagues from the Johns Hopkins School of Public Heath concluded that currently available data regarding an association between TRT and CV events are conflicted.40 At this time, a detailed discussion with patients about the risks and benefits of TRT is essential until further data is available. The eligibility criteria for this analysis included all placebo-controlled studies that enrolled men (1) with low or low-normal testosterone levels, and (2) who received any testosterone formulation for ≥ 3 months. Given emerging evidence from basic-science models, it is reasonable to assume that TRT positively affects the exercise capacity of CHF patients via a peripheral mechanism, such as promoting increased type I muscle fiber proliferation.27 Four authors have investigated the effects of TRT on exercise capacity in men with CHF. Testosterone supplementation resulted in a statistically significant increase in SDNN, SDANN, TP, LF, ULF, and very‑low‑frequency domain. Moreover, total power (TP) as well as high- and low‑frequency domains (HF and LF, respectively) were significantly lower in the MS+TDS+ group compared with the MS+TDS- group. Improving Cardiovascular Function Through Testosterone Replacement Therapy Testosterone replacement therapy (TRT) is a treatment option that has gained...