Heart rate and blood pressure responses to isometric exercise in young and older men

Abstract

The aim of this study was to examine the isometric endurance response and the heart rate and blood pressure responses to isometric exercise in two muscle groups in ten young (age 23-29 years) and seven older (age 54-59 years) physically active men with similar estimated forearm and thigh muscle masses. Isometric contractions were held until fatigue using the finger flexor muscles (handgrip) and with the quadriceps muscle (one-legged knee extension) at 20%, 40%, and 60% of the maximal voluntary contraction (MVC). Heart rate and arterial pressure were related to the the individual's contraction times. The isometric endurance response was longer with handgrip than with one-legged knee extension, but no significant difference was observed between the age groups. The isometric endurance response averaged 542 (SEM 57), 153 (SEM 14), and 59 (SEM 5) s for the handgrip, and 276 (SEM 35), 94 (SEM 10) and 48 (SEM 5) s for the knee extension at the three MVC levels, respectively. Heart rate and blood pressure became higher during one-legged knee extension than during handgrip, and with increasing level of contraction. The older subjects had a lower heart rate and a higher blood pressure response than their younger counterparts, and the differences were more apparent at a higher force level. The results would indicate that increasing age is associated with an altered heart rate and blood pressure response to isometric exercise although it does not affect isometric endurance.

Cardiorespiratory Response to Dynamic and Static Leg Press Exercise in Humans

“…Such a static exercise is essentially the same as "rhythmic isometric exercise" (Asmussen, 1981). During static, one-legged knee extension at 20%, 40%, and 60% MVC, continuously increasing HR and BP were observed, where the exercise duration at 20% MVC was the longest (4.6 min on average) (Smolander et al, 1998 unilaterally or bilaterally for 3 or 6 minutes, comparing the difference between the cases in both a dynamic and a static mode with two different intensities, 20% MVC and 40% MVC.…”

Attenuated Increases in Blood Pressure by Dynamic Resistance Exercise in Middle-Aged Men

“…Understanding the pressor response during dynamic resistance exercise using large muscle groups is essential for exercise prescription. However, most previous studies have focused on static resistance exercise (11,12,16,33), and have provided little information regarding the cardiovascular response during dynamic resistance exercise (10), or the interaction between age and BP response to dynamic resistance exercise using large muscle groups. We found that pressor responses during dynamic resistance exercise at relative intensities were lower in middle-aged than in young men, suggesting that the BP response to dynamic resistance exercise may be attenuated with advancing age despite age-associated arterial stiffening.…”

“…Systolic and diastolic blood pressures (BPs) rise rapidly to extremely high values during heavy weight-lifting exercise (10), and BPs are extreme even when exercise is performed with a relatively small muscle mass (11,12). Most previous studies have focused on the BP responses to resistance exercise in young adults (13)(14)(15), and thus have provided little information regarding BP responses in middle-aged and older individuals (12,16). Furthermore, the interaction between age and BP response for dynamic resistance exercise using large muscle groups has not been reported in middle-aged men with stiffening arteries or young men with compliant arteries.…”

Resposta hemodinâmica aguda a uma sessão de exercício físico multicomponente em idosos

“…Respostas mais exuberantes, não observadas no presente estudo, quer da FC, quer da PA ao exercício físico, podem, juntamente com as patologias cardiovasculares características deste escalão etário, aumentar significativamente o "stress" cardiovascular e, consequentemente, aumentar o factor de risco associado à exercitação (26,30) . A utilização simultânea dos membros superiores e inferiores durante os períodos do aquecimento e da resistência aeróbia poderão justificar os maiores valores de FC e PA, uma vez que a sobrecarga fisiológica é maior no exercício realizado com as extremidades superiores em comparação com aquele empreendido pelas extremidades inferiores (35) .…”