Peak cardiopulmonary exercise data for healthy Saudi males.

The use of cardiopulmonary exercise testing as a measure of functional capacity has increased substantially in recent years. Yet local normative data are remarkably lacking. Therefore, this study presents normal peak cardiopulmonary exercise values for 94 healthy Saudi males between the ages of 20 and 47 years. Graded exercise testing was performed using electronic cycle ergometer starting with 20 watts (W) and increasing work load (WL) by 10 W every minute until fatigue. Gas exchange parameters were continuously assessed using open circuit spirometry. Data were analyzed for three age groups: G1 (20-29 yr., n= 38), G2 (30-39 yr., n=36) and G3 (40-47 yr., n= 20). The findings indicated that absolute peak oxygen uptake (VO2 peak (L/min)) values were 2.22 ± 0.32, 2.23 ± 0.29 and 1.97 ±0.29 for G1, G2 and G3, respectively (G3 different from G1 and G2, p< 0.05). Respective values of VO2 peak relative to body mass (ml/kg.min) for G1, G2 and G3 were 31.6 ±5.9, 28.9 ±5.5 and 24.4 ±3.6 (G3 different from G1 and G2, p< 0.01). Maximal heart rate (HR max) dropped from 183 ± 8 bpm in G1 to 171±9 bpm in G3, with significant differences (p< 0.05) between the three groups. Maximal WL averaged 151.4 ±20.9 W for the whole group (ranged from 100 to 220 W). In addition, absolute VO2 peak had the highest correlation with exercise time (r = 0.81, p> 0.000), WL max (r = 0.78, p< 0.000), HR at WL 120 W (r = 0.67, p< 0.000), and thigh muscles strength (r = 0.40, p> 0.000). It was concluded that VO2 peak data presented in this study appear lower than those values reported for adult males of comparable age, weight and height in Western countries. Furthermore, these normal values of peak cardiopulmonary responses for healthy Saudi males would be very useful in interpreting maximal exercise data in Saudi patients suffering from cardiopulmonary impairments.Corresponding Author: Dr. Abdurahman M. Alhowaikan Exercise Physiology Laboratory, Dept. of P. E. and Movement Sciences, and Exercise Pulmonary Laboratory, Dept. of Medicine, King Saud University, PO Box 151645, Riyadh 11777, Saudi Arabia. Email: [email protected]

Adaptive RS-group scheduling for WiMAX multihop relay

IEEE 802.16j Multihop Relay (MR) is an optional deployment introduced to enhance the coverage and performance of WiMAX network without the need for deploying costly Base Stations (BSs). Multihop Relay network comprises of Multihop Relay BS (MRBS) and Relay Stations (RSs). This paper proposes mesh topology for IEEE 802.16j using adaptive RS group scheduling. The proposed scheduling algorithm introduces new signalling to support functions such as soft and hard horizontal-RS neighbour scanning, bandwidth request, forwarding of PDUs and connection management. The proposed model is evaluated using NS-2 network simulation. The simulation result shows that the proposed scheduling achieves higher throughput performance compared to IEEE 802.16j tree-topology