Effect of Aerobic Exercise at Different Intensities on Intraocular Pressure in Young Males : Journal of Glaucoma

Secondary Logo

Journal Logo

New Understandings of Glaucoma: Original Studies

Effect of Aerobic Exercise at Different Intensities on Intraocular Pressure in Young Males

Alfaqeeh, Fatima PhD*; Djemai, Haidar PhD†,‡; Hammad, Rami MSc§,∥; Hammad, Saleh MSc; Noirez, Philippe PhD†,‡,∥,#; Dabayebeh, Ibrahim M. PhD§

Author Information
doi: 10.1097/IJG.0000000000002110
  • Free

Abstract

Exercise has historically been considered an integral part of a healthy lifestyle. Over recent years, exercise has been described as a nondrug treatment for many people suffering from various illnesses including heart diseases, diabetes, high blood pressure (BP), and obesity.1,2 Also, its effects on several physiological variables are still debated or even unknown, pointing to the need for more research. This can include exploration of changes in intraocular pressure (IOP) during exercise by healthy subjects, athletes, and the ill.3

IOP is the pressure created by the continued renewal of fluids within the eye. Its main physiological determinant is the balance between the production of aqueous humor secreted from ciliary processes of the posterior chamber (2/3), on the one hand, and passive ultrafiltration through blood vessels on anterior surfaces of the iris at an overall rate of 2 µL/min (1/3), on the other. The aqueous humor is eliminated through the trabecula of the episcleral venous system and ultimately using the Schlemm canal, which lies at the iridocorneal angle.4–6 Previous studies reported different ranges of IOP values deemed normal, varying between individuals in relation to BP and ocular perfusion pressure. Vera et al7 indicated that trained individuals exhibited more stable IOP and BP responses to maximal physical effort, whereas greater IOP and BP changes were observed for their untrained group, and there were no significant differences in ocular perfusion pressure between these groups. Another study reported that 95% of young adults have an IOP in the range of 10–21 mm Hg, which was considered normal for members of this population with normal BP.8 IOPs outside of this range indicate an abnormal situation that required a visit to the ophthalmologist. Visual skills and fluctuations in IOP are unfortunately not measured during exercise.9 Risner et al10 stated that “IOP has been one of the parameters most commonly used to assess the effect of physical exercise on ocular function.” Physical exercise, especially aerobic exercise, plays an important role in IOP fluctuations. In general, however, because IOP monitoring during physical activity is difficult, it is not clear, which factors contribute to these fluctuations.3,11 Other difficulties may be insufficient sampling rates, making it hard to capture IOP variability, and improper tonometer manipulation and positioning during measurements.3,12

The conflicting and limited data available may reflect differences in participant profiles between studies, and in the kind, duration, and intensity of exercise performed.11,13–17 Various studies have focused on IOP fluctuation and recovery time after exercise without clearly addressing other factors, such as time of day, subjects’ levels of physical fitness, and environment. Recent studies have noted a decrease in IOP after certain forms of endurance and resistance training17–19 and after strength training.11 The effect of aerobic exercise intensity on levels of IOP fluctuation has not, however, been elucidated. IOP kinetics during aerobic exercise has also not been described. Accordingly, the main objective of this study was to investigate the effect that different aerobic exercise intensities have on IOP and its correlation with physiological variables.

METHODS

Participants

A total of 20 healthy, active males (mean age: 21.45±1.73 y; mean weight: 69.75±9.37 kg; mean height: 174.75±4.77 cm) voluntarily participated in this study after signing written consent forms. Only nonsmokers who had not taken any medication during the previous 3 weeks were included. Al-Ahliyya Amman University Research Ethics Committee approval was obtained (code: 3/1-2020/2021) for this research, which adhered to the tenets of the Declaration of Helsinki.

Study Protocols

Before the 4 test sessions, subjects each attended an orientation session during which they signed an informed consent form and detailed their medical and training histories.

A repeated measures design was used, requiring the completion of 4 test sessions. During the first session, after a 1-minute warm-up, subjects pedaled their cycle ergometer (Monark) at a constant rate of 60 rpm as the workload was increased every 3 minutes. Peak power (W) corresponded to the intensity reached at the time of a subject’s volitional exhaustion.

Subjects returned to the physiology laboratory 48 hours later for the first of 3 tests lasting 25 minutes each. These tests were conducted at low (50% of peak power), moderate (70%), and high (85%) intensities, respectively; spaced 48 hours apart; and all took place at the same time of day (Fig. 1). In addition, subjects were informed about the intensity of each test.

F1
FIGURE 1:
Study procedure. First session: the power of the cycle ergometer (Monark) increased by 60 W every 3 minutes until volitional exhaustion; power at the time of exhaustion is subject’s peak power. Last 3 sessions conducted at progressively higher intensities (at 50%, 70%, and 85% of peak power, respectively). In addition to IOP, other variables evaluated were HR; DBP and SBP; BG; BL; visual acuity; and RPE. The evaluations were carried out at the beginning of each session, after every 5 minutes of exercise, and 5 minutes after the end of each exercise. The duration of each evaluation was 2 minutes. BG indicates blood glucose; BL, blood lactate; DBP, diastolic blood pressure; HR, heart rate; IOP, intraocular pressure; L, left eye; R, right eye; RPE, rating of perceived exertion; SBP, systolic blood pressure.

IOP was recorded using a tonometer (iCare@ TA01i, Icare Finland, Finland) allowing quick and easy measurement without anesthesia for both eyes at once, before each of the 4 sessions, during short rest periods of 2 minutes after the performance sessions of 5, 10, 15, 20, and 25 minutes after the start of each session, and 5 minutes after the end of each session. Heart rate (HR), blood glucose (BG), blood lactate (BL), BP, both diastolic blood pressure (DBP) and systolic blood pressure (SBP), the Borg rating of perceived exertion scale (RPE, the level of exertion was quoted from 6 “no exertion at all” to 20 “maximal exertion”),20 and visual acuity (E Eye Chart test) were also measured at these time points. The blood was drawn from the earlobe to examine lactate using the lactate scout device (EKF Diagnostics, UK) and from the finger to examine glucose using the glucoDr device (Allmedicus, South Korea). All samples were drawn from subjects in the same seated position on the ergometer to avoid confounding factors. Any observed changes may thus be expected to reflect exercise intensity rather than body position.

Statistical Analysis

Data were expressed as means with standard deviations. All statistical analyses were performed using R software (version 3.6.2, R Foundation for Statistical Computing, Vienna, Austria). After evaluating homogeneity of variance using the Levene test (P>0.05), we realized a linear mixed model approach, which here corresponds to a 2-way repeated-measures analysis of variance evaluating interactions between the effects of the various intensities (ie, low, moderate, and high) for all time points (ie, before; at 5, 10, 15, 20, and 25 min, respectively; and after each session). The main effect of each independent variable (time and intensity) was tested, as well as the effect of the interaction. Simultaneous tests for general linear hypotheses on all significant effects were used as post hoc analyses with Bonferroni corrections. Finally, the relationships between IOPs for different exercise intensities and other variables were analyzed using the Spearman correlation. The statistical significance threshold was set at P<0.05.

RESULTS

The peak power of each participant was evaluated to calculate the different exercise intensities (low, moderate, and high) for each individual. The peak power assessment on the cycle ergometer as measured for the group of participants: 213±21.5 W.

Plots of mean IOP (left, right, and both eyes) for the low, medium, and high-intensity sessions, at each time point, are provided in Figure 2. A significant reduction in IOP was observed during high-intensity exercise (85%) in both eyes (P<0.05). IOP began to decline 5–10 minutes after the start of the high-intensity sessions and continued to fall until the final postsession time point. This trend was not observed for low and medium exercise intensities.

F2
FIGURE 2:
Change in IOP during aerobic exercise of various intensities. Participants completed 25-minute exercise sessions at 50%, 70%, and 85% of peak power, respectively. Mean IOP before, during, and after sessions for (A) right eye (note significant decrease in IOP at 15 minutes, for high-intensity session), (B) left eye, (C) both eyes (note significant decrease at 10 min, for high-intensity session). Colors represent different exercise intensities (see key). Solid circles, triangles, and squares represent means; bars show SDs. For a given exercise intensity, means with different lowercase letters (a, b, c) are significantly different (P<0.05). At a given time point, means (for different exercise intensities) surrounded by dotted circles that are joined by a dotted line are also significantly different (P<0.05) (linear mixed models with repeated-measures analysis of variance and simultaneous tests for general linear hypotheses). IOP indicates intraocular pressure.

Table 1 shows the mean values of the physiological variables for each aerobic exercise intensity level and time point. We observed a significant increase in HR, SBP, and BL during exercise at the different intensities. HR rose from the start of the test regardless of intensity. HR rose in parallel with RPE. DBP increased during exercise at moderate and high intensities only. An increase in BL is especially apparent at medium and high intensities and is correlated with RPE (r=0.55, P<0.001), but BL fell 5 minutes after the sessions. We noted significant increases in HR, DBP, and BL at high intensity, relative to other intensities, which is matched by significant increases in RPE throughout the exercise session. However, visual acuity (diopters) was not affected by the increase in intensity.

TABLE 1 - Changes in Physiological Variables as a Function of Duration and Intensity of Aerobic Exercise
Intensity Intensity Effect
Variables Times (min) L: 50% M: 70% H: 85% L-M L-H M-H
HR (bpm) Before 73.55±13.67a 77.80±8.70a 75.50±9.57a 0.74 1.00 1.00
5 118.50±19.01b 136.10±15.42b 150.85±17.54b <0.001 <0.001 <0.001
10 130.40±15.75c 148.95±15.96c 158.90±13.42b <0.001 <0.001 0.02
15 135.25±15.76c 154.25±17.27cd 165.35±11.91c <0.001 <0.001 0.008
20 137.40±13.87c 158.25±15.66cd 166.95±11.63c <0.001 <0.001 0.06
25 140.60±11.91c 161.00±15.13d 167.65±11.40c <0.001 <0.001 0.21
After 96.75±10.55d 97.95±5.90e 102.15±10.34d 1.00 0.42 0.76
Diastolic blood pressure (mm Hg) 5 83.40±6.74a 84.30±8.01a 90.95±7.55a 1.00 0.01 0.04
10 86.95±8.62a 86.50±7.85a 96.95±7.76ab 1.00 <0.001 <0.001
15 89.00±9.70a 91.30±8.63ab 100.80±10.08bc 1.00 <0.001 0.001
20 89.90±7.98a 94.00±9.85bc 104.35±10.00bc 0.36 <0.001 <0.001
25 89.30±9.52a 95.70±9.35bc 104.65±6.67c <0.05 <0.001 0.002
Systolic blood pressure (mm Hg) 5 126.85±9.52a 130.90±9.96a 140.15±12.81a 0.75 <0.001 <0.05
10 132.35±10.30a 137.45±12.14ab 147.15±10.78ab 0.45 <0.001 <0.05
15 139.30±18.38b 142.55±12.78ab 151.75±12.80b 1.00 <0.01 <0.05
20 138.95±8.33b 145.80±13.61bc 155.95±12.35b 0.16 <0.001 <0.05
25 139.40±9.73b 148.30±14.12c 155.15±11.02b <0.05 <0.001 0.18
Blood lactate (mmol/dm3) Before 1.65±0.54a 1.45±0.52a 1.69±0.68a 1.00 1.00 1.00
5 2.46±0.87ab 3.46±1.15ab 4.71±2.20bc 0.48 0.005 0.23
10 4.24±1.49b 4.70±2.69bc 6.21±2.43bc 1.00 0.02 0.10
15 3.92±1.12b 5.38±2.12bc 7.40±2.97bc 0.11 <0.001 0.01
20 3.79±2.58ab 5.70±2.71c 8.13±2.52bc 0.02 <0.001 0.002
25 4.03±2.54b 5.90±2.22c 8.44±2.03b 0.02 <0.001 0.001
After 3.28±4.48ab 4.22±2.12bc 6.03±1.97c 0.55 <0.001 0.03
Visual acuity R (D) Before 4.86±0.06 4.85±0.12 4.85±0.08 1 1 1
5 4.87±0.06 4.83±0.11 4.82±0.09 0.12 0.07 1
10 4.84±0.06 4.85±0.07 4.84±0.08 1 1 1
15 4.85±0.06 4.84±0.08 4.81±0.08 1 0.20 0.77
20 4.84±0.06 4.83±0.10 4.83±0.08 1 1 1
25 4.84±0.05 4.83±0.06 4.82±0.06 1 1 1
After 4.87±0.04 4.85±0.10 4.86±0.05 1 1 1
Visual acuity L (D) Before 4.87±0.06 4.87±0.11 4.84±0.09 1 0.58 0.58
5 4.86±0.07 4.83±0.11 4.84±0.09 0.58 0.83 1
10 4.81±0.07 4.83±0.11 4.84±0.08 0.83 0.38 1
15 4.85±0.08 4.83±0.11 4.83±0.08 1 1 1
20 4.86±0.07 4.83±0.10 4.84±0.08 0.83 1 1
25 4.85±0.06 4.83±0.10 4.82±0.07 0.83 0.58 1
After 4.84±0.07 4.83±0.08 4.85±0.06 1 1 1
RPE 5 8.65±1.98a 9.35±1.78a 10.01±3.49a 0.49 <0.05 0.55
10 10.85±2.23b 11.80±1.82b 13.30±2.25b 0.17 0.002 <0.001
15 12.20±2.46bc 13.45±1.98bc 15.80±2.26c <0.05 <0.001 0.004
20 12.85±2.68bc 14.50±2.25c 17.20±1.85c <0.01 <0.001 <0.001
25 13.85±2.66c 16.55±2.06d 18.65±1.53c <0.001 <0.001 0.01
Values are presented as mean±SD.
Results with different superscript letters (a, b, c, d, e) are significantly different (P<0.05).
Visual acuity (D) was measured by the E Eye Chart test.
RPE scale (the level of exertion was quoted from 6 “no exertion at all” to 20 “maximal exertion”).
Intensity effect: L (low): 50%, M (moderate): 70%, H (high): 85%; P-value (Linear mixed models with repeated-measures analysis of variance and simultaneous tests for general linear hypotheses).
HR indicates heat rate; RPE, rating of perceived exertion; Visual acuity R, visual acuity right; Visual acuity L, visual acuity left.

IOP is correlated with certain physiological variables, RPE, and exercise time points at high intensity alone. In contrast, there was no relationship with visual acuity at any exercise intensity. We noted statistically significant relationships between BP (DBP and SBP) and IOP (DBP: R=−0.34, P<0.001; SBP: R=−0.31, P<0.01). A significant correlation also exists between BL and IOP (R=−0.28, P<0.001), and at a high intensity between RPE and IOP (R=−0.59; P<0.001).

DISCUSSION

This study attempted to track changes in IOP before, during, and after aerobic exercise at various intensities, and to our knowledge, it is the first investigation of its kind. We observed an intensity-dependent decrease in IOP during and after aerobic exercise at 85% intensity (Fig. 2). This reduction in IOP after aerobic or resistance exercise has been the subject of various investigations,11,14–18,21–24 as has its relationship with the workload.19,25–27 But most of these studies measured IOP only before and after exercise but not during exercise, nor at different intensities.3,15,21,24

Our results reveal a progressive drop in IOP during high-intensity activity, starting at 10 minutes and continuing until 5 minutes after the end of the exercise. This corresponds to a decrease in pressure of ∼5 mm Hg (∼29%). McMonnies3 reported in his review that a decrease in IOP is observed after 9 minutes of moderate intensity activity on an exercise bike. The same was observed in runners, which means left-eye IOP immediately after exercise was 6.13 mm Hg lower than the baseline value.28 McMonnies3 also reports that IOP fluctuations are significantly related to exercise intensity and duration. Studies have shown that IOP fell significantly after maximal short-term aerobic exercise by 5.9±0.6 mm Hg.29,30 Moreover, among marathon runners, longer exercise at moderate intensity decreased IOP by only 2.25 mm Hg.25 However, 25-minute periods of low (50% of peak power) and moderate (70%) exercise did not affect IOP values for both eyes, which were found to be within the “normal rest” range.

The mechanism of postexercise decreases in IOP remains unclear and various hypotheses have been advanced to explain IOP reduction.3 It is possible that the increase in respiratory rate and amplitude caused by higher CO2 levels during high-intensity aerobic exercise have an effect similar to that of the Valsalva maneuver during high-intensity resistance exercise where IOP tends to increase. This agrees with our data, which revealed a correlation between decreased IOP and increased BL during high-intensity exercise. Schuman et al23 have confirmed the influence of respiratory variations on IOP, they showed that playing wind musical instruments is linked to increased IOP and is closely correlated with the magnitude of expiration.

In contrast, our statistical analyses indicated an increase in HR and a decrease of IOP in both eyes at 15 and 20 minutes after starting high-intensity exercise, but no linear quantitative correlation. The same has been observed in runners.31 These findings challenge the idea that there is a causal relationship between HR and BP variations and IOP changes.3,14

Previous studies have suggested that long-term intermittent increases in IOP might be linked to glaucomatous pathologic changes.23 The potential contribution of supine high-resistance exercise, facial muscle tension, and the Valsalva maneuver should also be clarified.32 Measurement of facial muscle tension and both metabolic and ventilatory changes during aerobic and anaerobic exercise would enable sounder conclusions to be drawn in relation to IOP changes.

Data from the present study show a significant interaction (P<0.05) between exercise duration (5, 10, 15, 20, and 25 min) and intensity (50%, 70%, or 85% of peak power). Conte et al21 found that 30 minutes of high-intensity interval training had a hypotensive effect on IOP. Intensity seems to be a factor in postexercise IOP reduction. A previous study whose findings bear similarity to our own has concluded that there is a potential interaction between duration and intensity.33 This again may be linked to increased ventilation or physiological by-products during high-intensity exercise over longer periods.3 As exercise sessions in our study all lasted 25 minutes, we cannot offer any conclusions about the effects of different durations. An earlier study suggested that extended exercise duration was the reason for visual impairment in marathon runners.34 Our results revealed relationships between IOP and certain physiological variables during high-intensity exercise, but no connection with visual acuity changes. We noted significant relationships between BP (DBP and SBP) and IOP. These observations agree with those of Vera et al,15 who suggested a moderate positive association between IOP and DBP at different measurement time points. Our study also found BL and RPE to be significantly related to IOP. Vera et al35 likewise demonstrated a correlation between IOP and RPE for physical activity. They also concluded that rapid measurement of IOP could serve as a marker of sensitivity to perceived exertion.

The present study indicates that high-intensity aerobic exercise results in a ∼29% drop in IOP for both eyes. Our data do not suggest a progressive decrease in IOP as exercise intensity increases; low and moderate-intensity aerobic exercise was not associated with significant changes in IOP.

Our decision, not to measure IOP >30 minutes after the end of an exercise session, may constitute a limitation of this study. Measuring indirect calorimetry (O2 consumption and CO2 production) during physical exercise might also be helpful to understand the role O2 and CO2 play in decreasing IOP.36 In addition, Vera et al7 suggested that abnormal central corneal thickness might affect IOP. Our study did not take this factor into consideration and cannot exclude its potential impact on our results. Additional research on this topic, as it pertains to sports, is needed. Another limitation of our study is that these results cannot be extrapolated to the general population, especially the elderly. Additional studies in this population, which represents the main population at risk of developing glaucoma.

CONCLUSION

The intensity and duration of aerobic exercise play an important role in reducing IOP in young adults. Our study is unique in that its findings help predict how IOP changes during aerobic exercise. Higher exercise intensity may lead to a greater reduction in IOP during exercise. This reduction may be driven by multiple physiological factors affected by physical exercise. Although low and moderate-intensity exercise did not lower IOP, aerobic exercise is still recommended and encouraged for glaucoma patients.

REFERENCES

1. Pedersen BK, Saltin B. Exercise as medicine—evidence for prescribing exercise as therapy in 26 different chronic diseases. Scand J Med Sci Sports. 2015;25(suppl 3):1–72.
2. Warburton DER, Bredin SSD. Health benefits of physical activity: a systematic review of current systematic reviews. Curr Opin Cardiol. 2017;32:541–556.
3. McMonnies CW. Intraocular pressure and glaucoma: is physical exercise beneficial or a risk. J Optom. 2016;9:139–147.
4. Carreon T, van der Merwe E, Fellman RL, et al. Aqueous outflow—a continuum from trabecular meshwork to episcleral veins. Prog Retin Eye Res. 2017;57:108–133.
5. Goel M, Picciani RG, Lee RK, et al. Aqueous humor dynamics: a review. Open Ophthalmol J. 2010;4:52–59.
6. Machiele R, Motlagh M, Patel BC. Intraocular pressure. StatPearls. Treasure Island (FL): StatPearls Publishing; 2019.
7. Vera J, Jiménez R, Redondo B, et al. Effect of a maximal treadmill test on intraocular pressure and ocular perfusion pressure: the mediating role of fitness level. Eur J Ophthalmol. 2020;30:506–512.
8. Wang YX, Xu L, Wei WB, et al. Intraocular pressure and its normal range adjusted for ocular and systemic parameters. The Beijing eye study 2011. PLoS One. 2018;13:e0196926.
9. Yip JLY, Broadway DC, Luben R, et al. Physical activity and ocular perfusion pressure: the EPIC-Norfolk eye study. Invest Ophthalmol Vis Sci. 2011;52:8186–8192.
10. Risner D, Ehrlich R, Kheradiya NS, et al. Effects of exercise on intraocular pressure and ocular blood flow: a review. J Glau coma. 2009;18:429–436.
11. Vera J, Raimundo J, García-Durán B, et al. Acute intraocular pressure changes during isometric exercise and recovery: the influence of exercise type and intensity, and participant´s sex. J Sports Sci. 2019;37:2213–2219.
12. Otsuka M, Tojo N, Hayashi A. Error in measurement of intraocular pressure with the Icare and IcarePRO. Int Ophthalmol. 2020;40:439–445.
13. Fujiwara K, Yasuda M, Hata J, et al. Long-term regular exercise and intraocular pressure: the Hisayama study. Graefes Arch Clin Exp Ophthalmol. 2019;257:2461–2469.
14. Najmanova E, Pluhacek F, Botek M. Intraocular pressure response to moderate exercise during 30-min recovery. Optom Vis Sci. 2016;93:281–285.
15. Vera J, García-Ramos A, Jiménez R, et al. The acute effect of strength exercises at different intensities on intraocular pressure. Graefes Arch Clin Exp Ophthalmol. 2017;255:2211–2217.
16. Vera J, Jiménez R, Redondo B, et al. Fitness level modulates intraocular pressure responses to strength exercises. Curr Eye Res. 2018;43:740–746.
17. Vera J, Jiménez R, Redondo B, et al. Acute intraocular pressure responses to high-intensity interval-training protocols in men and women. J Sports Sci. 2019;37:803–809.
18. Esfahani MA, Gharipour M, Fesharakinia H. Changes in intraocular pressure after exercise test. Oman J Ophthalmol. 2017;10:17–20.
19. Natsis K, Asouhidou I, Nousios G, et al. Aerobic exercise and intraocular pressure in normotensive and glaucoma patients. BMC Ophthalmol. 2009;9:6.
20. Borg GA. Psychophysical bases of perceived exertion. Med Sci Sports Exerc. 1982;14:377–381.
21. Conte M, Baldin AD, Russo MRRR, et al. Effects of high-intensity interval vs. continuous moderate exercise on intraocular pressure. Int J Sports Med. 2014;35:874–878.
22. Krejci RC, Gordon RB, Moran CT, et al. Changes in intraocular pressure during acute exercise. Am J Optom Physiol Opt. 1981;58:144–148.
23. Schuman JS, Massicotte EC, Connolly S, et al. Increased intraocular pressure and visual field defects in high resistance wind instrument players. Ophthalmology. 2000;107:127–133.
24. Yan X, Li M, Song Y, et al. Influence of exercise on intraocular pressure, Schlemm’s canal, and the trabecular meshwork. Invest Ophthalmol Vis Sci. 2016;57:4733–4739.
25. Leighton DA, Phillips CI. Effect of moderate exercise on the ocular tension. Br J Ophthalmol. 1970;54:599–605.
26. Qureshi IA. Effects of mild, moderate and severe exercise on intraocular pressure of sedentary subjects. Ann Hum Biol. 1995;22:545–553.
27. Shapiro A, Shoenfeld Y, Shapiro Y. The effect of standardised submaximal work load on intraocular pressure. Br J Ophthalmol. 1978;62:679–681.
28. Singh DR, Madan DR, Rani DN, et al. Effect of aerobic exercise on intraocular pressure in young individuals Invest Ophthalmol Vis Sci. 2017;16:41–43.
29. Harris A, Malinovsky V, Martin B. Correlates of acute exercise-induced ocular hypotension. Invest Ophthalmol Vis Sci. 1994;35:3852–3857.
30. Passo MS, Goldberg L, Elliot DL, et al. Exercise conditioning and intraocular pressure. Am J Ophthalmol. 1987;103:754–757.
31. Karabatakis VE, Natsis KI, Chatzibalis TE, et al. Correlating intraocular pressure, blood pressure, and heart rate changes after jogging. Eur J Ophthalmol. 2004;14:117–122.
32. Silvia ES, Raczynski JM, Kleinstein RN. Self-regulated facial muscle tension effects on intraocular pressure. Psychophysiology. 1984;21:79–82.
33. Wasserman K. Diagnosing cardiovascular and lung pathophysiology from exercise gas exchange. Chest. 1997;112:1091–1101.
34. Williams PT. Relationship of incident glaucoma versus physical activity and fitness in male runners. Med Sci Sports Exerc. 2009;41:1566–1572.
35. Vera J, Jiménez R, García JA, et al. Baseline intraocular pressure is associated with subjective sensitivity to physical exertion in young males. Res Q Exerc Sport. 2018;89:25–37.
36. Xie Y, Yang Y, Han Y, et al. Association between arterial blood gas variation and intraocular pressure in healthy subjects exposed to acute short-term hypobaric hypoxia. Transl Vis Sci Technol. 2019;8:P2.
Keywords:

aerobic exercise; intensities; intraocular pressure (IOP); blood lactate; blood pressure

Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.