On Jan. 22, 2025, South Coast AQMD issued a smoke advisory for the Hughes Fire that named Santa Clarita among the areas expected to be hit hardest. The agency advised residents to stay indoors with windows and doors closed, run air conditioning or an air purifier, and avoid vigorous physical activity.
CAL FIRE reported that the Hughes Fire burned 10,425 acres near Castaic Lake, and in October 2019 the Tick Fire burned 4,615 acres in Canyon Country. On days like that, indoor cardio on smoky days starts with checking the Air Quality Index (AQI), the shared scale for deciding whether to exercise outside, move indoors or rest.
What Do the AQI Colors Mean for Your Workout?
The six AirNow AQI levels pair a number range with a color and a health message:
- 0–50, Good (green): Air quality is satisfactory, and air pollution poses little or no risk.
- 51–100, Moderate (yellow): Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution.
- 101–150, Unhealthy for Sensitive Groups (orange): Members of sensitive groups may experience health effects. The general public is less likely to be affected.
- 151–200, Unhealthy (red): Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects.
- 201–300, Very Unhealthy (purple): Health alert: The risk of health effects is increased for everyone.
- 301+, Hazardous (maroon): Health warning of emergency conditions: everyone is more likely to be affected.
EPA defines sensitive groups as people with heart or lung disease, older adults, children and teens, pregnant people, and outdoor workers. If you or someone in your household is in one of these groups, follow the more cautious advice for each level.
EPA’s 2023 Air Quality Guide for Particle Pollution gives outdoor activity advice for each level. At Good, it is a great day to be active outside. At Moderate, unusually sensitive people should consider making outdoor activities shorter and less intense; for everyone else, it is a good day to be active outside. At Unhealthy for Sensitive Groups, sensitive groups should make outdoor activities shorter and less intense. At Unhealthy, sensitive groups should avoid long or intense outdoor activities. Everyone else should reduce them. At Very Unhealthy, sensitive groups should avoid all outdoor physical activity, and everyone else should avoid long or intense activities. At Hazardous, everyone should avoid all outdoor physical activity.
Where to Check Santa Clarita’s Air Before You Head Out
Before a run, walk, or trip to the park, open the AirNow Fire and Smoke Map. EPA and the U.S. Forest Service run the map, which displays readings from official monitors as well as low-cost sensors with an EPA correction applied.
Use the NowCast AQI on the AirNow Fire and Smoke Map to judge whether now is a good time to go out. Check the value for the area you plan to visit rather than relying on yesterday’s conditions or a valley-wide guess.
South Coast AQMD also posts smoke advisories for the region, so check those too. Smoke can vary across the valley and change during the day. Check again before you leave if you head out later, and look at the map again if conditions appear different while you are out.
Is the Air Inside Your Home Really Better?
Moving a workout indoors does not by itself settle the air-quality question. EPA notes that particle levels can be high inside when they are high outdoors, because smoke can enter through openings and indoor air can also contain particles from household activities.
EPA’s smoke guidance recommends keeping windows and doors closed. Set central HVAC to recirculate, if that setting is available. Use a MERV 13 filter if your system allows it; check the equipment instructions or ask a qualified HVAC professional if you are unsure what the system can handle. A portable air cleaner should be sized for the room and should not produce ozone.
You can designate one room as a “clean room.” Spend time there with doors and windows closed and filtration running. Pick one with enough floor space to move safely. Filtration can reduce exposure indoors, though smoke may remain.
While smoke is present, EPA also advises avoiding activities that add particles or increase breathing demand: skip frying food and burning candles, and avoid strenuous activity. If the room feels stuffy or the air quality changes, stop and reassess rather than assuming that closed windows have solved the problem.
Indoor Cardio on Smoky Days: A Gentle Routine
South Coast AQMD and EPA advise avoiding vigorous or strenuous activity during smoky periods, so this routine stays at a light-to-moderate effort. Choose movements that let you control your pace and stop easily. Marching in place, step-touch, a stationary bike or a mini-trampoline, a low-impact indoor option, can all work.
Try this 15-minute sequence, reducing the time or range of motion to suit your current ability:
- Settle in, 3 minutes: Walk gently around a clear area or march with relaxed arms. Let your breathing find a comfortable rhythm.
- Move steadily, 8 minutes: Alternate one minute of marching with one minute of side-to-side step-touch, repeating the pattern four times. Keep your steps small; if you use another piece of equipment instead, maintain the same easy-to-moderate effort.
- Ease out, 4 minutes: Slow the march, then stand or sit and let your breathing return toward its usual pace.
Use the talk test to check intensity. At moderate effort you should be able to talk, though singing would be difficult. If you can only get out a few words before pausing for breath, ease the pace or stop. Keep the routine conversational.
For a first session, try a few minutes before deciding whether to continue. If you are older, returning after a break, or have a condition that affects exercise, choose movements and duration that fit any advice you have received from your health professional. Keep a chair or wall nearby for balance if useful, and clear the floor before you start.
When Should You Skip the Workout Altogether?
Skip the session if current public-health guidance calls for avoiding activity, or if you feel unwell, dizzy, unusually short of breath, or have symptoms that concern you. On Very Unhealthy or Hazardous days, or when smoke is getting into your home, rest is the better choice. Follow local public-health instructions and seek medical advice for symptoms that require it; a missed workout can wait.
Keeping Your Weekly Minutes on Track
A smoke day may interrupt your usual schedule, but the weekly target can be built from smaller sessions on days when conditions and your plans allow. The 2018 Physical Activity Guidelines for Americans recommend adults aim for 150–300 minutes of moderate-intensity activity a week, or 75–150 minutes of vigorous-intensity activity.
Under the guidelines, any amount of activity counts. Activity no longer needs to come in bouts of at least 10 minutes. A short walk around the house or a brief gentle session can contribute to your total. Add the minutes across the week when you can, and let air-quality guidance determine which days belong indoors or are better used for rest.
