The Effects of High Intensity Interval Exercise in Obese

Experimental: Obese Subjetcs

The subjects were welcomed for a visit to the Laboratory of Studies of Physical Training Applied to Health, where they performed an evaluation of body composition, maximal ergospirometric exercise test, and three experimental sessions (HIIE 1, HIIE 3 and Control) in a random order, which were performed with a 96 h interval between them.

Procedimiento: HIIE 1

In the HIIE 1 session, all the subjects performed 10 stimuli of 1 min at high intensity (92% of VO2Max) with passive recovery (without exercise) of 1 min.

Procedimiento: HIIE 3

In the HIIE 3 session, the subjects performed the same stimulus of the HIIE1, but with passive recovery of 3 min. Both protocols started with a warm-up of 5 min at 50% of the VO2Peak performed on a T2-100 GE Healthcare® treadmill (Lynn Medical, Wixon, Michigan, USA).

Procedimiento: Control

In the control session, participants remained seated for 30 min. During HIIE 1 and 2, HR and RPE were assessed immediately after stimulus intervals (ten measurements at each HIIE). In all sessions, the subjects remained in supine position to obtain hemodynamic measurements which were obtained before and at 10 min, 30 min and 60 min after the HIIE and control sessions.

Forearm Blood Flow and Vascular Conductance

Forearm muscular blood flow was obtained through the venous occlusion plethysmography technique (19). For this, a silicon tube filled with mercury and connected to a low-pressure transducer was placed around the forearm, 5 cm away from the humeral-radial joint, connected to a plethysmograph (Hokanson® / EC6 plethysmograph, Bellevue, Washington, USA). A cuff was placed around the wrist and another at the upper arm, and the wrist cuff was inflated to a supra-systolic level every 1 min before measurements start. The arm cuff was inflated above the venous pressure at 10 s intervals for a period of 7 to 8 s. The increase in tension in the silastic tube reflects the increase in the volume of the forearm, which indicates vasodilation. The muscle flow wave signal was collected and stored on the WINDAQ DI 200 DATAQ program. Vascular conductance in the forearm was calculated by the blood flow ratio in the forearm (mL.min-1.100mL-1) and mean arterial pressure (mmHg) multiplied by 100.

Blood pressure

Blood pressure values were obtained in a non-invasive manner, using an oscillometric method (Dixtal®, DX 2020; Manaus, Amazonas, Brazil). The occlusive cuff was positioned on the left ankle of the subject and was inflated minute by minute, providing systolic (SBP), diastolic (DBP) and mean (MBP) blood pressure values. For electrocardiogram (ECG) acquisition, three electrodes were placed on the thorax of the subjects in the bipolar position and DII derivation. After pre-amplification of the ECG signal, a conversion from analog to digital was performed, and later stored in a computer and processed by the WINDAQ DI-200 program (WinDaq DI-200, Akron, Ohio).

Heart rate

Heart rate was monitored throughout the exercise session using a Polar RS800CX monitor (Polar®, Kempele, Finland).