The purpose of this study was to examine acute hematological and mood perception responses to supplementation with p‐synephrine alone and in combination with caffeine during quiet sitting. Sixteen subjects visited the laboratory on 6 occasions and were given (in randomized double‐blind manner) 103‐mg p‐synephrine (S), 233‐mg caffeine + 104‐mg p‐synephrine, 240‐mg caffeine, 337‐mg caffeine + 46‐mg p‐synephrine, 325‐mg caffeine, or a placebo (PL). The subjects sat quietly for 3 hr while completing mood state questionnaires every 30 min. Venous blood samples were collected at baseline (pre) and 3 hr (post) to determine immune, lipid, and chemistry panels. Compared with PL, no significant supplement differences were observed during the S trial with the exception of differential time effects seen in hematocrit (decrease in PL, no change in S), triglycerides and very low‐density lipoproteins (no changes in PL, significant decreases in S), and iron (no change in PL, significant elevation in S). Supplements containing caffeine showed increased feelings of attention, excitement, energy, and vigor. These data indicate that consumption of 103‐mg p‐synephrine does not negatively impact acute blood parameters, does not augment the effects of caffeine, or produce stimulant‐like perceptual mood effects.

This investigation examined the interactive effect of body-weight (BW) exercises and vibration on cardiometabolic responses. Fourteen subjects performed a BW exercise protocol with (BW+V) and without (BW‒V) vibration in a randomized order. The BW exercise protocol consisted of three circuits of eight calisthenics-based exercises including prisoner squat, push-up, isometric squat, reverse dip, lunge, flutter kicks, isometric lunge, and T push-up. Vibratory frequency and amplitude were set at 40 Hz and 4 mm, respectively. Oxygen uptake (VO2), heart rate (HR), expired ventilation (VE), and blood lactate [La] were determined during the protocol and 30-minute recovery. The mean VO2 reached 48% and 50% of VO2max and the mean HR reached 80% and 83% of HRmax in BW‒V and BW+V, respectively. During the protocol, while the mean VE was greater (p=.031) in BW+V than BW‒V, no differences were seen for VO2 and HR between the two conditions. During recovery, while mean VO2 was greater (p=.002) in BW+V than BW-V, no differences were seen for VE and HR between the two conditions. [La] values were significantly elevated but remained similar between the two conditions. Exercise-specific VO2 was higher during the prisoner squat (p=.003) and isometric squat (p=.042) in BW+V than BW‒V, while no differences in VO2 were observed for all other exercises. Performing three circuits of eight BW exercises in a rapid-and-intense manner produced a sufficient increase in cardiometabolic responses. Metabolic potentiation associated with combining vibration with BW exercises seemed to be influenced by how the exercises were carried out on a vibration plate.

The purpose was to examine cardiovascular responses to supplementation with p-synephrine alone and in combination with caffeine during quiet sitting. Sixteen subjects were given (in double-blind manner) either 103mg of p-synephrine (S), 233mg of caffeine +104mg of p-synephrine (LC+S), 240mg of caffeine (LC), 337mg of caffeine +46mg of p-synephrine (HC+S), 325mg of caffeine (HC), or a placebo. The subjects sat quietly for 3hr while heart rate (HR) and blood pressure were measured. Only HC+S and HC significantly increased mean systolic blood pressure (SBP) during the second hour and tended to increase mean SBP during the third hour. Mean diastolic blood pressure in S was significantly lower than the other trials during the first and second hours, and mean arterial pressure was significantly lower in S compared to the LC, LC+S, HC, and HC+S trials. No differences were observed in HR. Consumption of p-synephrine may acutely reduce diastolic blood pressure and mean arterial pressure and not affect SBP or HR during quiet sitting. The addition of p-synephrine to caffeine did not augment SBP or HR indicating that consumption of up to 104mg of p-synephrine does not induce cardiovascular stress during quiet sitting.

The purpose of this study was to examine the acute cardiorespiratory and metabolic effects of a sandbag (SB) resistance exercise protocol and compare the responses to time-matched treadmill running protocols. Eight healthy, resistance-trained men (21.1 +/- 1.0 years; 86.1 +/- 7.8 kg) completed 4 protocols of equal duration in random sequence: (a) SB, (b) treadmill running at 60% of (V) over doto(2) reserve (60(V) over doto(2)R), (c) treadmill running at 80% of (V) over doto(2) reserve (80(V) over doto(2)R), and (d) a control protocol. The SB protocol was 16 minutes in duration and consisted of 3 circuits of 8 multiple-joint exercises (with 11-, 20-, or 48-kg SBs) performed for as many repetitions as possible for 20 seconds followed by a 10-second rest interval before beginning the next exercise. Two minutes of rest was allowed between circuits. Breath-by-breath oxygen consumption ((V) over doto(2)) and heart rate (HR) were recorded throughout each protocol and for 30 minutes postexercise (PE) and blood lactate was determined before and immediately after each protocol. Blood lactate was significantly higher after SB compared with 60(V) over doto(2)R and 80(V) over doto(2)R. Mean and peak HR in SB was significantly higher than 60(V) over doto(2)R but not different from 80(V) over doto(2)R. Mean (V) over doto(2) and energy expenditure (EE) in SB was significantly lower than 60(V) over doto(2)R and 80(V) over doto(2)R during each protocol but significantly higher after SB compared with 60(V) over doto(2)R and 80(V) over doto(2)R PE. Compared with 60(V) over doto(2)R and 80(V) over doto(2)R, respiratory exchange ratio was significantly higher during SB and through 5 minutes PE, but was significantly lower at 2530 minutes PE after SB. Sandbag, as performed in this study, provides a superior metabolic stimulus to treadmill running during the PE period; however, the SB results demon strate inferior EE compared with running at 60(V) over doto(2)R and 80(V) over doto(2)R.

Ratamess, NA, Kang, J, Porfido, TM, Ismaili, CP, Selamie, SN, Williams, BD, Kuper, JD, Bush, JA, and Faigenbaum, AD. Acute resistance exercise performance is negatively impacted by prior aerobic endurance exercise. J Strength Cond Res 30(10): 2667-2681, 2016-The purpose of the present study was to examine acute resistance exercise (RE) performance after 4 different aerobic endurance (AE) protocols. Eleven healthy, resistance-trained men (21.0 ± 1.2 years) performed a control RE protocol and 4 RE protocols 10 minutes after different AE protocols in random sequence. The RE protocol consisted of 5 exercises (high pull, squat, bench press, deadlift, and push press) performed for 3 sets of 6-10 repetitions with 70-80% of one repetition-maximum (1RM) with 3-minute rest intervals in between sets. The AE protocols consisted of treadmill running at velocities corresponding to: (a) 60% of their V[Combining Dot Above]O2 reserve (V[Combining Dot Above]O2R) for 45 minutes (P1); (b) 75% of their V[Combining Dot Above]O2R for 20 minutes (P2); (c) 90-100% of V[Combining Dot Above]O2R in 3-minute intervals (1:1 ratio) for 5 sets (P3); and (d) 75% of V[Combining Dot Above]O2R (4.5 mph) uphill (6-9% grade) for 20 minutes (P4). Completed repetitions, average power and velocity, heart rate (HR), and ratings of perceived exertion (RPE) were assessed each set. Protocols P1-P4 resulted in 9.1-18.6% fewer total repetitions performed compared with the control RE protocol with the squat experiencing the greatest reduction. Average power and velocity were significantly reduced for the high pull, squat, and bench press after most AE protocols. Ratings of perceived exertion values for the high pull and squat were significantly higher in P1-P4 compared with control. Heart rate was significantly higher during RE after P1-P4 compared with control by 4.3-5.5%. These results indicate acute RE performance is significantly compromised in healthy men after AE exercise of different type, intensity, and duration with largest reductions observed after high-intensity interval exercise.