The control group will undergo the same testing procedures outlined above, but they will be asked to maintain their current level of activity and normal daily habits for the duration of the intervention.

During the exercise session, HR will be measured via a Polar heart rate strap (Kempele, Finland). The training sessions will consist of six 90-second high-intensity cycling (HIC) sprints performed on a cycle ergometer (Monark Ergomedic 895E, Monark, Varberg, Sweden) at 80-90% VO2max, followed by 180 seconds of low-intensity cycling (LIC) at 50-60% of VO2max. During both HIC and LIC intensities, participants will be asked rate of perceived exertion, which will be compared to the participants' heart rate throughout the exercise sessions. This supervised training protocol will require 9 minutes of HIC at 80-90% VO2max and 18 minutes of LIC at 50-60% VO2max. The cycling session will begin with a brief warm-up and end with a cool-down down totaling the entire supervised exercise session for 30 minutes. Training sessions will be performed 48 hours after the previous training session for a total of 3 times per week on Mondays, Wednesdays, and Fridays.

The breathing intervention will consist of a daily breathing practice lasting 5 to 10 minutes for 5 days per week. Breathing practice is a form of cyclic hyperventilation consisting of 30 breath (inhalation and exhalation) repetitions followed by an exhaled breath retention for 15 seconds during the first week and up to 30 seconds during the second week. A total of 3 rounds will be performed by the participants. Participants will be instructed to perform breathing repetitions in a controlled and consistent manner while either seated or lying down. Participants will receive guided instruction via a video on breath cycle queues, informing the participants when to inhale, exhale, and when to retain their breath while being supervised by the research team via Zoom call. Upon completion of the breath training sessions, the research team will conduct a guided cooldown and check in with all participants to ensure they are feeling no adverse side effects from the breathing exercise.

Participants assigned to this intervention group will complete 6 supervised HIIT sessions over 2 weeks.

Approximately 60 mL of whole blood will be collected into serum separator tubes (Beckton Dickinson, East Rutherford, NJ, USA), allowed to clot for 30-min at room temperature, and then centrifuged at 2000 RPM for 15 min. The serum will be pipetted into 1.5 mL microcentrifuge tubes (Eppendorf AG, Hamburg, Germany) and immediately stored in a -80 °C freezer. Serum concentrations of CRP will be determined with a commercially available enzyme-linked immunosorbent assay (ALPCO Diagnostics, Salem, NH, USA). Microplates will be read with an ELx800 BioTek microplate reader (BioTek Instruments, Inc., Winooski, VT, USA) at the recommended wavelength of 450 nanometers.

Approximately 40 mL of whole blood will be collected into serum separator tubes (Beckton Dickinson, East Rutherford, NJ, USA), allowed to clot for 30 minutes at room temperature, and then centrifuged at 2000 RPM for 15 min. The serum will be pipetted into 1.5 mL microcentrifuge tubes (Eppendorf AG, Hamburg, Germany) and immediately stored in a -80 °C freezer. Serum concentrations of BDNF (Sigma-Aldrich, St. Louis, MO, USA) will be determined with commercially available enzyme-linked immunosorbent assays. Microplates will be read with an ELx800 BioTek microplate reader (BioTek Instruments, Inc., Winooski, VT, USA) at the recommended wavelength of 450 nanometers.

15mL of whole blood will be obtained using sodium heparin tubes and a peripheral venous puncture. Blood samples will be mixed with Dulbecco's phosphate buffer solution (DPBS) at a 1:1 ratio and layered over 20 mL of Ficoll gradient matrix. Blood samples will be centrifugation at 111 x g for 40 minutes, acceleration 7, brake 0 (Eppendorf 5810R centrifuge, Hamburg, Germany). Samples will be washed 3 times, then resuspended at 1.0 * 10^6 cells/mL and incubated for 4 hours at 37 degrees Celsius, with 5% CO2. Next, samples will be pelleted, resuspended, and antibody-receiving samples will each receive 500uL DPBS and 1uL of Fragment crystabillize blocker (FcB)/1.0*10^6 cells and incubate on ice for 20 minutes. Samples will be pelleted, resuspended in 500uL DPBS and receive 500uL of DPBS and 2uL of CD56 (NCAM) monoclonal antibodies, incubate on ice for 20 minutes, pelleted, and resuspended in 1mL of DPBS, then analyzed using an Attune NXT flow cytometer (Thermo Fischer, Waltham, MA).

PAR-Q+ utilizes yes or no generalized health questions to screen participants interested in engaging in an exercise program for the need of medical clearance and physician release. The PAR-Q+ has 7 general health questions ranging from Does the participant feel chest pain at rest or during activities of daily living? Individuals who are eligible for this investigation require no further medical clearance before participating in an exercise program and should truthfully answer NO to every question. Participants who answer "Yes" to any questions will be required to answer follow-up questions to determine the need for medical clearance. If medical clearance is suggested, the individual will not be eligible to participate.

Height will be obtained in centimeters (cm)( using a stadiometer SECA 220 (Chino, California, USA).

Weight will be obtained in kilograms (kg) using a Detecto standing digital scale (Webb City, Missouri, USA).