KOBAYASHI, Y., J.A. LOEPPKY, M.D. VENTERS, and U.C. LUFT. Circulation and respiration response to arm exercise and lower body negative pressure.Med. Sci. Sports Exercise, Vol. 12, No. 4, pp. 244–249, 1980: The effects of supine arm exercise and lower body negative pressure (LBNP) were studied in six subjects with 10 min of LBNP at −40 mmHg (L), arm cranking for 8 min at a work load of 225 kpm/min (E) and both combined (L + E) preceded by 2 min of LBNP. Initial responses of ventilation (&OV0312;1) and &OV0312;2were curtailed and heart rate was significantly higher after the first min of L + E than E, reflecting the less accessible venous reservoir and reduced stroke volume due to L. Leg volume was significantly reduced after 30 s of E and continued to decline and remained below baseline during 6 min of recovery. With L + E, leg volume remained constant after E began, indicating both a shift of blood from legs to arms and reduced extravasation with LBNP. End-tidal PO2, &OV0312;1and &OV0312;1/&OV0312;o2were higher and Pco2lower during the latter stages of L + E than during E, indicating less effective lung perfusion and greater alveolar deadspace caused by LBNP. The release of pooled blood from the lower body after L+E caused a greater &OV0312;1, &OV0312;o2and lower RE than after E and produced marked transients in Pco2and Po2, thereby slowing the recovery of gas exchange.