Aerobic vs. strength training: what to do and how much

“Should I do cardio or lift weights?” is the wrong question, and answering it wrong costs carriers real protection. The answer is both, because they guard different parts of you, and the practical problem is not choosing between them but fitting them into one week without them fighting each other. That fit is what this page is about.

If you want the case for why exercise is the top lever at all, that lives in exercise and APOE4. Here we assume you are sold and you want the weekly plan.

Two jobs, not one

The shortest way to hold the difference in your head:

• Aerobic (cardio) builds the engine. It improves cardiovascular fitness, blood pressure, and metabolic health, and it is the form most studied for brain and cognitive benefits (blood flow, BDNF, amyloid-related signals). Brisk walking, cycling, swimming, jogging.
• Strength builds the chassis. Resistance work preserves muscle and bone, supports insulin sensitivity, and protects your ability to function and stay independent as you age. It becomes non-negotiable past midlife, for reasons covered in strength training after 50.

For an APOE4 carrier, running both together covers nearly every system implicated in risk: vascular, metabolic, and neurological. You are not double-dipping; you are closing different gaps.

Sequencing them in one week

The only real wrinkle when you do both is recovery. Hard intervals and heavy lifting compete for it. This is the “interference” effect, and it is real but modest for most people, so you manage it rather than fear it.

Two rules handle almost all of it:

1. Separate your hardest cardio day from your hardest lifting day. Give each its own day so neither is done on tired legs.
2. If you must stack them, lead with whatever matters more that day. The second exercise is done slightly fatigued, so put your priority first.

Easy zone-2 walks barely cost any recovery, so they slot in on the other days without conflict. A sample week that respects all of this:

Day	Session
Mon	Strength (full body)
Tue	Easy zone-2 walk
Wed	Hard cardio (one interval session)
Thu	Easy zone-2 walk
Fri	Strength (full body)
Sat	Longer easy walk or ride
Sun	Rest or gentle movement

That is two strength days, one hard cardio day, and easy aerobic volume filling the gaps. Scale it down freely; the structure matters more than the exact count.

Sensible weekly targets

Standard adult guidance is a reasonable anchor (adapt to your health and your clinician’s advice):

• Aerobic: at least 150 minutes a week of moderate activity, or about 75 minutes vigorous, or a mix. Brisk walking counts. The upper half of the range (toward 300 minutes) adds further benefit.
• Strength: muscle-strengthening activity on 2 or more days a week, covering the major muscle groups (legs, hips, back, chest, shoulders, arms, core).
• Some is far better than none. Benefits start well below the targets, so a partial routine still counts for a lot.

How to program each session

You do not need a complicated plan.

• Strength, 2 to 3 days. One or two sets to start (building to two or three) of 6 to 10 exercises covering the major groups, roughly 8 to 12 reps each. Progressive overload is the engine: gradually add weight, reps, or sets so the muscle keeps adapting.
• How hard should a set feel? Stop a rep or two short of failure, roughly a 7 to 8 out of 10 on perceived effort. Enough to drive adaptation without grinding yourself down.
• Aerobic, most days. Follow the 80/20 rule: about 80% easy “conversational” zone 2 effort, and 20% hard. “Hard” means something concrete, like one weekly interval session (the 4x4: four rounds of 4 minutes near-hard with 3 minutes easy between) to push VO2max.
• Equipment is not the point. Bodyweight, bands, machines, or free weights all work. The best tool is the one you will use; start with whatever is least intimidating.

Putting it together safely

1. Build the aerobic base first if you are starting out. Daily walks qualify.
2. Add the strength sessions. They can be short; 20 to 30 minutes is plenty to start.
3. Increase slowly. A rough “10% a week” cap on jumps in volume helps avoid injury.
4. Check with your doctor before a vigorous program, especially with existing conditions.
5. Protect consistency over perfection. A routine you keep for years beats an optimal one you quit in a month. On busy weeks, lean on exercise snacks.

Common questions

If I only have time for one, which wins? Build the aerobic base first for general health. But do not neglect strength, especially past 50, when muscle loss accelerates. Even two short strength sessions a week matter.

Do I need a gym? No. Bodyweight strength work (sit-to-stands, push-ups, lunges, carries) and walking or cycling cover the essentials.

How long until it helps my brain? Vascular and metabolic improvements begin within weeks; the cognitive benefits are a long game measured in years, which is the case for starting now and staying consistent.

The best plan blends cardio and strength, fits your life, and survives contact with a busy week. Done consistently, it is the closest thing to a broad-spectrum brain-and-heart intervention we have. This is general education, not medical advice.