| ObjectiveThis study explored the variation of the heart rate and blood pressure of the pilots in the submaximal treadmill exercise,understood the regularity of blood pressure and heart rate changes under exercise load,and explored the value of blood pressure and heart rate changes in the study of flight adaptability under exercise load conditions.MethodsA total of 230 male pilots were selected to perform physical examinations at the Air Force General Hospital from December 2015 to December 2016.All selected pilots were flighter pilots,age(28±5)years,height(174±4)cm,and weight(71±7)kg.Clinical and laboratory tests were performed to remove secondary hypertension and other chronic diseases,and recently no antihypertensive drugs and other cardiovascular drugs were taken.The subjects' age,height,weight,time of flight,hemodynamic parameters(brachial-ankle pulse wave velocity,ankle-brachial pressure index,toe-brachial pressure index)were recorded,and body mass index BMI was calculated.Subjects walk on an active tablet and grade automatically according to Bruce's exercise program.Gradually increase the plate speed and slope every 3 minutes to adjust the load until the heart rate reaches the expected heart rate of the subject(submaximal target heart rate = 195-years.The second minute blood pressure(systolic pressure SBP and diastolic pressure DBP)was collected and recorded for each load phase of the submaximal exercise.The 12-lead automatic monitoring of the heart rate per minute was recorded and the peak blood pressure and heart rate were immediately measured.The Kruskal-Wallis rank sum test was used to compare the changes in blood pressure during each phase and heart rate at per minute of exercise.According to the results of exercise blood pressure,the subjects were divided into exaggerated exercise blood pressure group(peak systolic blood pressure?200mm Hg,diastolic blood pressure increased by 10 mm Hg or ?90mm Hg,n=210)and normal exercise blood pressure group(peak systolic blood pressure <200mm Hg,Diastolic blood pressure increased by <10mm Hg or <90mm Hg,n=20).The Mann-Whitney rank sum test was used to compare the differences in hemodynamic parameters between the exaggerated exercise blood pressure group and the normal exercise blood pressure group.Trend analysis of variance was used to understand the trend of peak systolic pressure and recovery systolic blood pressure as resting systolic blood pressure increased.Results1.Changes in blood pressure during exercise: At the beginning of exercise,SBP was significantly higher,SBP at rest was significantly different from SBP at the 1st stage(P=0.000);SBP was gradually increased with the increase of exercise load,There was a significant increase in resting SBP and SBP at the 1st stage also between 2nd stage and 3rd stage SBP(P=0.006;P=0.000).In the later stages of exercise,SBP did not increase significantly: Stage 3 and 4,4 and 5,the increase was not significant(P=0.096;P=0.904),and there was a significant difference between peak SBP and resting SBP(P=0.000).DBP decreased from resting to the first stage: there was a significant difference between DBP at rest and DBP at the first stage(P=0.000);DBP did not change significantly during exercise: There was no significant difference in DBP in the 1rt stage and 2nd stage,2nd and 3rd load stage,3rd and 4th stage,and 4th and 5th load stage(P=0.875;P=0.624;P=0.081;P=0.880).There was a significant difference between peak and resting DBP(P=0.000).Changes in blood pressure during recovery: SBP decreased by 29.48 mm Hg(P=0.000)at 4 min after recovery from the peak SBP;decreased by 13.86 mm Hg at 6 min from 4 min(P=0.000);SBP did not decrease to Rest level after 6 min recovery(P=0.000).DBP was significantly lower than DBP at rest after exercise(P=0.000).DBP increased by 3.1mm Hg(P=0.000)at 4min after recovery,and increased by 2.33 mm Hg(P=0.000)at 6min compared to 4min.DBP did not return to resting level at 6 min after recovery(P=0.000).2.Changes in heart rate during exercise: As the exercise load increases,the heart rate increases significantly from the upper level load to the next level load: There was a significant difference between resting HR and 1st min HR in exercise,3rd and 4th min HR,6th and 7th min HR,9th and 10 th min HR(P=0.000),and the heart rate was stable within 3 minutes during the same load,and no significant increase was observed.Changes in heart rate during recovery: At the end of exercise,the 2nd min HR was significantly lower than the peak HR(P=0.000).Recovery of 4th min HR was lower than that of 2nd min HR,and 6th min HR was lower than 4th min HR(P=0.000,P=0.000).No return to resting level until 6 min(P=0.000).3.There was no significant difference in the general clinical parameters and hemodynamic parameters(ba PWV,ABI,TBI)between arterial blood pressure normal and exercise hypertensive groups(P>0.05).4.The peak SBP showed a linear trend with increasing resting SBP(P=0.000);and the d SBP(peak SBP-rest SBP),d SBP at the 4thmin during recovery(peak SBP decreased within 4 min after recovery=peak SBP-4th min SBP during recovery)and d SBP 6thmin(peak SBP within 6min recovery range=peak SBP-6min SBP)did not show a linear trend of increase or decrease with increasing resting SBP(P>0.05).Conclusions1.In this study,the increase of exercise SBP was large at the beginning,and then gradually decreased as the exercise load increased;DBP decreased at the beginning of exercise and did not change significantly during exercise.After the end of the exercise,the blood pressure gradually returned to rest.2.The heart rate increases with the increase of exercise load during the secondary exercise,and the heart rate rises significantly at the beginning of each stage of load increase and showed a marked increase in the inflection point,and the heart rate is relatively stable during the same stage of load.The heart rate dropped rapidly during the early recovery phase of the exercise,and then decreased slowly.3.Pilots with normal resting blood pressure levels will also have high blood pressure in the submaximal exercise test.However,their hemodynamic parameters are not significantly different from those in normal exercise blood pressure.Follow-up observations should be conducted to explore the relationship between high blood pressure and long-term cardiovascular and cerebrovascular diseases in flight personnel.4.In this study,peak SBP showed an upward trend with resting SBP levels.The systolic blood pressure increase d SBP,the systolic blood pressure recovery period d SBP at the 4th minute,the systolic blood pressure recovery period d SBP at the 6th minute,did not show a linear trend with the resting SBP level.The pressure increase d SBP and resting SBP levels tend to be broken lines,therefore,it is not possible to understand only the pilot's static blood pressure level.When assessing the cardiovascular function and accommodative ability of flight personnel,multiple indicators and combined analysis are required to reflect the true level of cardiovascular function.In the selection of physical examination items for flight students,a treadmill exercise test should be added to assess cardiac reserve through exercise stress tests. |
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