Continuous measurement of left ventricular performance during and after maximal isometric deadlift exercise

Premature Death in Bodybuilders: What Do We Know?

Premature deaths in bodybuilders regularly make headlines and are cited as evidence that bodybuilding is a dangerous activity. A wealth of research has revealed elite athletes typically enjoy lower mortality rates than non-athletes, but research on bodybuilder lifespan is surprisingly limited. Anabolic androgenic steroid (AAS) use is commonly cited as a key contributor to morbidity and premature mortality in bodybuilders, but this area of research is highly nuanced and influenced by numerous confounders unique to bodybuilding. It is quite possible that bodybuilders are at elevated risk and that AAS use is the primary reason for this, but there remains much unknown in this realm. As global participation in bodybuilding increases, and healthcare providers play a more active role in monitoring bodybuilder health, there is a need to identify how numerous factors associated with bodybuilding ultimately influence short- and long-term health and mortality rate. In this Current Opinion, we discuss what is currently known about the bodybuilder lifespan, identify the nuances of the literature regarding bodybuilder health and AAS use, and provide recommendations for future research on this topic.

The Acute Cardiorespiratory and Cerebrovascular Response to Resistance Exercise

Resistance exercise (RE) is a popular modality for the general population and athletes alike, due to the numerous benefits of regular participation. The acute response to dynamic RE is characterised by temporary and bidirectional physiological extremes, not typically seen in continuous aerobic exercise (e.g. cycling) and headlined by phasic perturbations in blood pressure that challenge cerebral blood flow (CBF) regulation. Cerebral autoregulation has been heavily scrutinised over the last decade with new data challenging the effectiveness of this intrinsic flow regulating mechanism, particularly to abrupt changes in blood pressure over the course of seconds (i.e. dynamic cerebral autoregulation), like those observed during RE. Acutely, RE can challenge CBF regulation, resulting in adverse responses (e.g. syncope). Compared with aerobic exercise, RE is relatively understudied, particularly high-intensity dynamic RE with a concurrent Valsalva manoeuvre (VM). However, the VM alone challenges CBF regulation and generates additional complexity when trying to dissociate the mechanisms underpinning the circulatory response to RE. Given the disparate circulatory response between aerobic and RE, primarily the blood pressure profiles, regulation of CBF is ostensibly different. In this review, we summarise current literature and highlight the acute physiological responses to RE, with a focus on the cerebral circulation.

Acute cardiovascular responses to leg-press resistance exercise in heart transplant recipients

BACKGROUND

Reduced skeletal muscle strength is characteristic of individuals following heart transplantation. Weight lifting exercise has been demonstrated as an effective means by which to increase muscular strength in other cardiac patients but the appropriateness of this form of exercise in heart transplant patients has not been investigated. The purpose of this study was to describe the cardiovascular responses of heart transplant patients to a single, prolonged bout of weight lifting training.

METHODS

Twenty-three heart transplant recipients were stratified into early (Early; 3 months; n=6), intermediate (Intermediate; 1-3 years; n=7) and late (Late; 5-14 years; n=10) post transplant groups and studied in four experimental conditions: supine rest, upright rest, single leg-press exercise (28 repetitions over 2 min 20 s at 50% 1 repetition maximum) and recovery. Swan-Ganz catheterization allowed measurement of right heart pressures and cardiac output by thermodilution. Systemic arterial pressures and heart rate were measured continuously using a non-invasive finger cuff.

RESULTS

Cardiac output increased by 30, 40 and 54% during exercise in Early, Intermediate and Late, respectively. Heart rate increased by 4.5% in Early compared to 11 and 16% increases in Intermediate and Late. At peak exercise, systolic blood pressures reached average values of 179+/-9, 180+/-14 and 176+/-8 mmHg in Early, Intermediate and Late, respectively. Average mean pulmonary artery pressure did not exceed 30 mmHg and average pulmonary wedge pressure did not exceed 15 mmHg in any group during the exercise.

CONCLUSIONS

These observations indicate that a lengthened set of single leg-press exercise at a moderate lifting intensity can be performed within safe and acceptable physiological limits in patients following heart transplantation. To better address the specific rehabilitation needs of heart transplant recipients, future research should focus on developing training programs which include weight lifting exercise.

Prolongation of left atrial augmentation after handgrip stress in coronary artery disease: observation using pulsed Doppler flowmetry

Although alterations in left ventricular diastolic filling dynamics have been observed during myocardial ischemia, few data exist regarding temporal changes in left ventricular filling during recovery. Therefore, the authors evaluated transmitral inflow pattern during and after handgrip exertion in coronary artery disease (CAD) by using Doppler echocardiography. The study population consisted of 18 normal (N) subjects and 47 patients with CAD. Of the CAD patients, 17 had coronary lesions associated with a limited area of underperfused myocardium (seven with good collateral circulation and 10 with distal lesions) (MILD), 15 patients exhibited a proximal lesion in a single vessel (SVD), and 15 patients had significant multivessel disease (MVD). Transmitral inflow velocities were continuously recorded at baseline, during handgrip exercise (50% of maximal for 1 minute), and for 5 minutes of recovery. Mean blood pressure, heart rate, early diastolic (E) and late atrial (A) inflow velocities, A/E ratio, and percent changes in E, A, and A/E from baseline were measured. In N and MILD, respectively, left ventricular inflow pattern returned to baseline at 3 minutes after handgrip (%E: 0.7 +/- 7.6%, 6.4 +/- 13.7%; %A: -0.2 +/- 7.9%, 3.1 +/- 6.5%; %A/E: -0.1 +/- 9.7%, -1.7 +/- 12.9%). In SVD and MVD, respectively, change in left ventricular inflow pattern was continued at 3 minutes after handgrip (%E: 7.2 +/- 9.4%, -4.3 +/- 17.2%, %A: 15.4 +/- 11.7%, 20.4 +/- 14.6%, %A/E: 7.9 +/- 10.0%, 29.2 +/- 25.6%). Increases in A and A/E in SVD and MVD were significantly higher than in N and MILD. Impaired left ventricular inflow pattern was observed at 3 minutes after handgrip in CAD, which may be reflected from prolonged impairment of diastolic function produced by ischemia. Therefore, temporal observation of left ventricular inflow pattern using the handgrip stress Doppler method may be useful for detection or follow-up of CAD.

Acute responses to resistance training and safety

Resistance training is widely used in fitness programs for healthy individuals of all ages and has become accepted as part of the exercise rehabilitation process for patients with coronary artery disease. It is only during the past decade that the acute circulatory responses to resistance exercise have been investigated directly, using intra-arterial measurement techniques and two-dimensional echocardiography. This review examines the factors that influence the acute circulatory responses to resistance training. These include the number of repetitions, the absolute and relative load, the muscle mass engaged in the lifting, the joint angle, and the Valsalva maneuver. There is discussion of the responses in patients with coronary artery disease and the effects of resistance training on the acute responses. The review ends with a discussion of the safety of this form of exercise and concludes that it is safe and appropriate for most healthy individuals and many of those with different diseases.

The morphologic consequences of systemic training

The development of echocardiography in the 1970s led to the flourishing of the study of the athlete's heart. From the earliest studies, it was apparent that athletes develop enlargement of the left ventricular cavity and thickening of myocardium in response to prolonged repetitive training. The changes in echocardiographic measurements are small and often within quoted normal ranges. By comparison to sedentary controls, however, left ventricular end-diastolic dimension is increased by approximately 10%, posterior wall dimension by 15% to 20%, and calculated mass by up to 45%.

Comparison of left ventricular function using isometric exercise Doppler echocardiography in competitive runners and weightlifters versus sedentary individuals

It is unclear whether cardiovascular responses to heavy isometric exercise are changed by intensive training. We evaluated the effects of this type of exercise on left ventricular (LV) function in athletes engaged in static and dynamic sport, compared with sedentary persons, and looked for peculiarities in static athletes' responses that might reflect adaptive mechanisms to their specific activity. The study population comprised 45 men (age 24 +/- 5 years): 29 dynamic and 16 static athletes (runners and weightlifters, respectively). The control group consisted of 20 age and gender-matched healthy sedentary persons. All performed 50% of maximal voluntary contraction on a whole-body isometric exercise device for 2 minutes. Echocardiographic calculations were determined at rest and exercise. Upon exercise, stroke volume, cardiac output, end-diastolic volume, and ejection fraction increased significantly in athletes, while end-systolic volume and systemic vascular resistance decreased. In sedentary persons, stroke volume and resistance remained unchanged, cardiac output and LV volumes increased, and ejection fraction decreased from 67 +/- 5% to 60 +/- 5% (p <0.01 compared with rest; p <0.0001 compared with athletes). Whereas peak flow velocity decreased from 103 +/- 10 to 81 +/- 6 cm/s in sedentary persons, it increased from 112 +/- 9 to 126 +/- 8 cm/s in the static group and from 120 +/-3 to 126 +/- 9 cm/s in the dynamic athletes (p <0.0001 compared with the sedentary group). Mean acceleration decreased in the sedentary group, remained unchanged among the dynamic athletes, and increased among the static athletes. We conclude that cardiovascular responses to heavy isometric exercise are modified by intensive training. Athletes, taken as a group, react differently and adapt better than sedentary individuals. Moreover, among them, those involved in static sport show an improved cardiovascular adaptation to this type of exercise.

Angiotensin-converting enzyme inhibition, autonomic activity, and hemodynamics in patients with heart failure who perform isometric exercise

Effects of angiotensin-converting enzyme inhibition (ACEI) on autonomic responses and hemodynamics in patients with congestive heart failure (CHF) subjected to isometric exercise have not been studied. We tested whether acute ACEI might influence the effects of isometric exercise in patients with CHF. In the first part of the study we showed that isometric exercise increased blood pressure in the control group and in the CHF group, whereas cardiac output increased only in the control group. Stroke volume remained unchanged in the control group, whereas it decreased significantly in CHF group. We next analyzed the effect of acute ACEI (5 mg ramipril) on the decrease in cardiac output during isometric stress in patients with CHF. During isometric exercise mean blood pressure and heart rate increased similarly in both groups. However, cardiac output decreased during placebo by -0.48 +/- 0.12 L/min (p < 0.01) but not during ACEI. Spectral analysis of blood pressure showed an increase (p < 0.01) in the high-frequency parasympathetic component from 7.3% +/- 3.6% to 18.1% +/- 9.5% after ACEI. norepinephrine plasma levels increased after isometric stress in the placebo group, whereas other hormones did not change. ACEI prevented the norepinephrine increase after isometric stress. Thus the decrease in cardiac output during isometric exercise in patients with CHF was prevented by acute ACEI. The effect of ACE inhibition may be related to reduced sympathetic activity.

Continuous measurement of blood pressure, heart rate and left ventricular performance during and after isometric exercise in head-out water immersion

Experiments were performed to determine the changes in blood pressure (BP), heart rate (HR) and left ventricular function during and after isometric knee extension during thermoneutral (35 degrees C) head-out water immersion (HWI) or in air. Seven healthy male subjects mean age 24 (SD 3) years kept their knees extended (60% maximal voluntary extension) until they reached exhaustion. The mean BP at rest was 80 (SD 10) and 78 (SD 8) mmHg [10.7 (SD 1.33) and 10.4 (SD 1.07)kPa] in air and during HWI, respectively, (NS). They increased progressively (P < 0.01) during contraction and reached maximal values of 148 (SD 22) and 143 (SD 26) mmHg [19.7 (SD 2.93) and 19.1 (SD 3.47)kPa] in air and in HWI, respectively, (NS). The mean HR at rest was 74 (SD 8) and 70 (SD 11) beats.min-1 in air and in HWI, respectively, (NS). They also increased progressively, (P < 0.01) and reached 126 (SD 14) and 118 (SD 17) beats.min-1 in air and in HWI, respectively, (NS). The changes in BP and HR during contraction in HWI tended to be smaller than those in air (NS). Left ventricular end diastolic diameters (dd) at rest in HWI were greater than those in air and were maintained at higher values during and after isometric contraction. In contrast, dd decreased during isometric contraction in air (P < 0.01). The change of left ventricular systolic diameters (ds) in HWI was no different to those in air. From these findings, isometric exercise in thermoneutral HWI would seem to be characterized by a greater dd than in air and this could be useful for patients with deconditioning effects such as orthostatic hypotension.

Differential responses in left ventricular diastolic filling dynamics with isometric handgrip versus isotonic treadmill exertion

Although the hemodynamic responses to isotonic and isometric exercise are different, few data exist comparing the response to left ventricular (LV) diastolic filling dynamics with these two forms of exertion. Therefore we performed Doppler examination before and at the end of isotonic and isometric exercise in 20 normal volunteers to define the differential responses of LV filling to these two forms of exertion. Transmitral inflow velocity signals from the apical view and phonocardiography were recorded before and at the termination of treadmill exercise (TRD) to 11 METs and handgrip (HG) 50% maximal for 2 minutes). Mean blood pressure (mBP), heart rate (HR), early diastolic (E) and late atrial (A) inflow velocities, mean acceleration rate (ACC) of E wave, time velocity integral of inflow (Ti), and isovolumic relaxation time (IRT) from second heart sound to onset mitral inflow were measured. Absolute changes from baseline were significantly different for the two forms of exertion: TRD versus HG: BP = 11 +/- 9 versus 36 +/- 10 mm Hg, HR = 37 +/- 16 versus 16 +/- 9 beats/min, E = 11.6 +/- 11.3 versus -7.0 +/- 9.4 cm/sec, A = 29.9 +/- 14.5 versus 14 +/- 12 cm/sec, ACC = 164 +/- 151 versus -56 +/- 135 cm/sec2, Ti = 1.9 +/- 3.0 versus -1.7 +/- 1.7 cm, and IRT = -12 +/- 9 versus 9 +/- 10 msec, all p < 0.0001 except for A, p < 0.001). Isotonic treadmill exercise resulted in enhanced early diastolic filling manifested by increases in E and ACC and a decreased in IRT. Conversely, isometric handgrip exercise produced evidence of reduced early filling including decreased E and ACC and slightly increased IRT. Thus the response of LV filling dynamics recorded by Doppler differs for isotonic and isometric exertion and likely reflects the variable pressure and flow alterations induced by these two forms of exertion.

Cardiac failure and dysrhythmias 6-19 years after anthracycline therapy: a series of 15 patients

The clinical course of late symptomatic anthracycline cardiomyopathy, and resultant changes of cardiac function, were described in 15 patients. They represented a subset of 300 patients who had cardiac evaluations to identify the prevalence of late cardiotoxicity more than 4 years after anthracycline therapy in these patients. The clinical course and all available cardiac evaluations including electrocardiography, continuous taped electrocardiography, echocardiography, radionuclide cardiac angiography, cardiac catheterization, and endomyocardial biopsy, of the 15 patients were reviewed. The patients had received 285-870 (median 540) mg/M2 of daunorubicin and/or doxorubicin 6-19 (median 12) years prior to the onset of late symptoms. Seven patients also had 2,100-4,000 cGy mediastinal radiotherapy. Five patients had required treatment for cardiac symptoms at the end of chemotherapy but 10 patients had no cardiac problems anteceding their late decompensation. Fractional shortening on echocardiogram at late decompensation was 8-20% (median 17%) and radionuclide left ventricular ejection fraction was 8-59% (median 38%). All were treated with digitalis and diuretics and 13/15 with afterload reduction, with at least transient improvement of symptoms. They were followed for 1-9 (median 3) years after late decompensation. One died of uncontrollable cardiac failure. Another underwent successful cardiac transplantation. Conduction abnormalities and dysrhythmias were present in 14/15 patients and 3 died suddenly. Two more had syncope, one requiring an automatic cardiac defibrillator. Endomyocardial biopsy or autopsy revealed hypertrophy and fibrosis in 10/10 patients. Our patients with early cardiac symptoms improved transiently but decompensated later and patients with no early symptoms developed cardiac symptoms more than 10 years after anthracycline therapy. Therefore, patients who have received anthracyclines should have continued cardiac evaluation.